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ABNER WELLBORN CALHOUN 

MEDICAL LIBRARY 

1923 



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A SYSTEM 



HUMAN ANATOMY 



GENERAL AND SPECIAL. 



BY ERASMUS WILSON, M.D., 

LECTURER ON ANATOMY, LONDON. 

FOURTH AMERICAN 
FROM THE LAST LONDON EDITION. 



EDITED BY 



PAUL B. GODDARD, A.M., M.D., 

FR.OFESSOR OF ANATOMY AND HISTOLOOY IN THE FRANKLIN MEDICAL COLLEGE 
OF PHILADELPHIA. 




C -"-fit-R T ~ c 



:,_ r .. 



WITH TWO HUNDRED AND FIFTY-ONE ILLUSTRATIONS 

BY GILBERT. 



PHILADELPHIA: 

LEA AND BLANCHARD, 
1949. 



Entered, according to Act of Congress,, in the year 1846, by 

LEA AND.BLANCHARD 

in the clerk's office of the District Court of the United States fur the 
Eastern District of Pennsylvania. - 




PRINTED BY C . S II K R M A N , 



0'v) 



TO 

I 

SIR BENJAMIN COLLINS BRODIE, BART., F.R.S. 

SERGEANT-SURGEON TO THE QUEEN, 
MEMBER OF THE INSTITUTE OF FRANCE, 

IN ADMIRATION OF THE HIGH ATTAINMENTS 

WHICH HAVE JUSTLY PLACED HIM 

IN THE FIRST RANK OF HIS PROFESSION, 

2Ei)is ffiBJorft 

IS RESPECTFULLY INSCRIBED 
BY 



THE AUTHOR 



4ft 



■V 



PREFACE. 



The Preface to this little volume may be written in a few words. It 
first saw the light in the spring of 1840, and now T , in the autumn of 1844, 
has reached its Third Edition. In this short period, less than five years, 
five thousand copies have been distributed among the Members of the 
Profession, many also taking their place in the libraries of Gentlemen, 
who, although not of the Profession, justly consider that some general 
knowledge of the structure of the body is an essential part of a liberal 
education. In the same period, a second edition of the work has appeared 
in America ; and a translation, from the pen of Dr. Hollstein, has been 
completed in Berlin. 

Thus the volume has quickly returned for review to the hands of the 
Author ; and he trusts that an examination of the second and present edi- 
tions will prove that he has not neglected this advantage. He has care- 
fully corrected such oversights and omissions as may have occurred in 
the completion of a work on so extensive a subject ; many parts which 
seemed scantily treated, he has entirely re-written ; and he has endea- 
voured to give as full a description of every point in Anatomy, whether 
important or trivial, as is consistent with the limits and objects of a Prac- 
tical Manual. 

Two features in the Anatomist's Vade Mecum appear to the Author to 
deserve notice: — the first relates to the labours of his professional bre- 
thren ; the second to the illustrations contained in the work. On the first 
of these heads the Author begs to remark, that he considers it a duty, as 
well to them as to his readers and himself, to quote all recent observations 
and discoveries in Anatomy which may have interest, and to give as 
complete an abstract of such discoveries as the scheme of the work will 
permit. By pursuing this plan, the Author trusts to distinguish his 
volume as the Record of the Profession at large, and not as the text-book 
merely of a particular school. And, in furtherance of his object, he has 

(vh) 



Vlll PREFACE. 

to request a continuance of those communications from scientific investi- 
gators, which have hitherto so materially aided him. 

The woodcut illustrations which accompany the Anatomist's Vade 
Mecum have been increased with each edition. Several of the new 
figures are illustrative of General Anatomy, and, to insure their absolute 
correctness, have been drawn from the microscope by the Author himself, 
with the aid of the camera lucida. Figures 13, 14, 15, showing the 
changes which occur during the development of bone ; figures 63-66, the 
minute anatomy of cartilage ; and figure 103, the structure of the ultimate 
muscular fibril, are examples of such drawings. The structure exhibited 
in the latter figure formed the subject of a paper which was read before 
the Royal Society during the present year. 

Upper Charlotte Street, Fitzroy Square, 
November, 1844. 



PREFACE 
TO THE FOURTH LONDON EDITION. 



In preparing the "Anatomist's Vade Mecum," for the fourth time, 
for the Press, the Author has availed himself of the discoveries, in Ana- 
tomy, which have been made public since the appearance of the preceding 
edition ; and he takes the opportunity, now afforded him, of acknowledg- 
ing his obligation to the several investigators whose researches he has 
quoted. To one gentleman, namely, to Mr. Paget of St. Bartholomew's 
Hospital, he feels particularly indebted for the assistance which he has 
derived from the excellent " Reports, on the chief results obtained by the 
use of the Microscope in the study of Human Anatomy and Physiology," 
published in the British and Foreign Medical Review. 

In the present edition of this volume, the Wood-cut Illustrations have 
been augmented to two hundred ; and the Author begs to observe that, 
with very few exceptions, which have been duly acknowledged, the whole 
of the subjects are original ; the drawings having been executed by Mr. 
Bagg from dissections prepared expressly for the work, or from drawings 
made by himself. The chief of the illustrations of General Anatomy were 
drawn from the microscope with the camera lucida, in order to ensure 
absolute correctness. 

Upper Charlotte Street, Fitzroy Square, 
March 1, 1847. 

(ix) 



PREFACE 
TO THE FOURTH AMERICAN EDITION. 



*+ W-s^/V\/W\/\/\/\/W>/N« 



The Editor, in presenting this new edition of Mr. Wilson's standard 
work on Anatomy, has found but little to add, the author having so com 
pletely revised and brought up his last edition ; while he has incorporated 
in the text many of the Editor's notes to former editions. 

A small increase in the size of the page has enabled the Publishers to 
take in the additional matter, while diminishing slightly the number of 
pages. 

The Editor has added some new matter and a large number of new cuts — 
among others an important series on the nerves — he has rewritten his in- 
troductory chapter on Histology; and he has taken every care to ensure, 
throughout, perfect correctness in the text. He thus hopes that the work 
will continue to hold the high character which its merits have acquired in 
this country, and to maintain its position as a standard Text Book for the 
student, which it has assumed in so many of our Colleges. 

The London edition is still known by the Author's original title of 
"Vade Mecum;" but the publishers consider themselves sustained in 
the change they have made, by the fulness and completeness of the work, 
which amply warrant for it the title of "A System of Human Anatomy." 

P. B. G. 

Philadelphia, July, 1848. 

(xi) 




CONTENTS. 



CHAPTER I 



HISTOLOGY. 



Page 
Definition 33 

Chemistry of the tissues 33 

Nitrogenized substances 35 

Non-nitrogenized substances 36 

Of the tissues 37 

Tabular view of the tissues 37 

Description of the tissues 38 

• 



Page 

Physical properties 39 

Vital properties 40 

Development of tissues 40 

Development of cells 41 

Multiplication of cells 41 

Transformation of cells 42 



CHAPTER II. 



OSTEOLOGY. 



Page 
Definition ..--.- .... 43 

Chemical composition of bone 43 

Division into classes 43 

Structure of bone 44 

Development of bone 46 

Period of ossification 48 

The skeleton 49 

Vertebral column - • . 50 

Cervical vertebrae 50 

Dorsal vertebrae 53 

Lumbar vertebrae 53 

General considerations 54 

Development 55 

Attachment of muscles 56 

Sacrum 56 

Coccyx 58 

The skull 58 

Bones of the cranium 58 

Occipital bone 59 

2 



Parietal bone 61 

Frontal bone 62 

Temporal bone 64 

Sphenoid bone 69 

Ethmoid bone 72 

Bones of the face 74 

Nasal 74 

Superior maxillary 74 

Lachrymal bone 77 

Malar bone 77 

Palate bone 78 

Inferior turbinated bone 80 

Vomer 80 

Inferior maxillary 81 

Table of developments, articulations, &c. 83 

Sutures 83 

Regions of the skull 84 

Base of the skull 86 

Face 89 

(xiii) 



XIV 



CONTENTS. 



Page 

Orbits 90 

Nasal fossae 90 

Teeth 92 

Structure 93 

Development 95 

Growth 97 

Eruption 98 

Succession 99 

Os hyoides 99 

Thorax and upper extremity 100 

Sternum 100 

Ribs 101 

Costal cartilages 102 

Clavicle 103 

Scapula 103 

Humerus 105 

Ulna 106 

Radius 107 



Page 

Carpal bones 109 

Metacarpal bones H2 

Phalanges 1 13 

Pelvis and lower extremity 1 14 

Os innominatum 1 14 

Ilium H4 

Ischium H5 

Os pubis H6 

Pelvis — Its Divisions — Axes — Dia- 
meters 117, 118 

Femur 119 

Patella 121 

Tibia 121 

Fibula 122 

Tarsal bones 124 

Metatarsal bones 127 

Phalanges 128 

Sesamoid bones 129 



CHAPTER III. 



THE LIGAMENTS. 



Page 

Forms of articulation 130 

Synarthrosis 130 

Amphi-arthrosis 1 30 

Diarthrosis 130 

Movements of joints 1.31 

Gliding 131 

Angular movement 131 

Circumduction 131 

Rotation 132 

General anatomy of articular structures 132 

Cartilage 132 

True cartilage 132 

Reticular cartilage 132 

Fibrous cartilage 134 

Fibrous tissue 134 

Ligament . . . , 135 

Tendon 135 

Adipose tissue 136 

Synovial membrane 136 

LlGAMENTS OF THE TRUNK ARRANGE- 
MENT 137 

Articulation of the vertebral column . . . 137 

Of the atlas with the occipital bone. . 140 

Of the axis with the occipital bone . . 141 

Of the atlas with the axis 141 

Of the lower jaw ; 142 

Of the ribs of the vertebrae 144 



Page 
Of the ribs with the sternum, and with 

each other 145 

Of the sternum * 146 

Of the vertebral column, with the 

pelvis 146 

Of the pelvis 146 

Ligaments of the upper extremity 149 

Sterno-clavicular articulation 149 

Scapuloclavicular articulation 151 

Ligaments of the scapula 151 

Shoulder joint 152 

Elbow joint , 152 

Radio-ulnar articulation 153 

Wrist joint 155 

Articulations of the carpal bones 156 

Carpo-metacarpal articulation 156 

Metacarpo-phalangeal articulation 157 

Articulation of the phalanges 158 

Ligaments of the lower extremity 158 

Hip joint 158 

Knee joint 1,59 

Articulation between the tibia and fibula 163 

Ankle joint j 64 

Articulation of the tarsal bones 165 

Tarso-metatarsal articulation 167 

Metatarsophalangeal articulation 167 

Articulation of the phalanges 168 



CONTENTS. 



XV 



CHAPTER IV. 

THE MUSCLES. 



Page 

General anatomy of muscle 1 68 

Nomenclature— Structure 169 

Muscles of the head and face 173 

Arrangement into groups 173 

Cranial group — Dissection 174 

Occipito-frontalis 174 

Orbital group — Dissection 175 

Orbicularis palpebrarum 175 

Corrugator supercilii 1 75 

Tensor tarsi — Actions 176 

Ocular group — Dissection 176 

Levator palpebrae — Rectus superior . . 177 
Rectus inferior — Rectus internus — 

Rectus externus 177 

Obliquus superior 178 

Obliquus inferior — Actions 178 

Nasal group 179 

Pyramidalis nasi — Compressor nasi. . 179 

Dilatator naris — Actions 179 

Superior labial group .. . 180 

Orbicularis oris — Levator labii superi- 
ors alseque nasi 180 

Levator labii superioris proprius 180 

Levator anguli oris — Zygomatici. . . . 180 
Depressor labii superioris alaeque nasi 181 

Actions 181 

Inferior labial group — Dissection 181 

Depressor labii inferioris . . . 181 

Depressor anguli oris — Levator labii 

inferioris 181, 182 

Actions 182 

Maxillary group 182 

Masseter — Temporal muscle 182 

Buccinator — External pterygoid mus- 
cle 183 

Internal pterygoid muscle 1 84 

Actions 184 

Auricular group — Dissection 184 

Attollens aurem 184 

Attrahens aurem 185 

Retrahens aurem — Actions 185 

Muscles of the neck 185 

A rrangement into groups 185 

Superficial group — Dissection 186 

Platysma myoides 186 

Sterno-cleido-mastoideus 186 

Actions 1 87 

Depressors of the os hyoides and larynx 187 

Dissection 188 

Sterno-hyoideus — Sterno-thyroideus. 188 
Thyro-hyoideus — Omo-hyoideus .... 188 

Actions 189 

Elevators of the os hyoides 189 

Dissection 189 

Digastricus 189 



Page 
Stylo-hyoideus — mylo-hyoideus 189, 190 
Genio-hyoideus — Genio-hyo-glossus — 

Actions 190 

Muscles of the tongue 191 

Hyo-glossus — Lingualis 191 

Sty lo-glossus 1 92 

Palato-glossus — Actions 192 

Muscles of the pharynx — Dissection. . . 192 

Constrictor inferior 192 

Constrictor medius — Constrictor supe- 
rior 193 

Stylo - pharyngeus — Palato- pharyn- 

geus — Actions 193, 194 

Muscles of the soft palate — Dissection. . 194 
Levator palati — Tensor palati. . .194, 195 

Azygos uvula? — Palato-glossus 195 

Palato-pharyngeus — Actions .... 195, 196 

Prevertebral muscles — Dissection 196 

Rectus anticus major — Rectus anticus 

minor 196 

Scalenus anticus 196 

Scalenus posticus — Longus colli. . . . 197 

Actions 198 

Muscles of the larynx 198 

Muscles of the trunk 198 

Muscles of the back — Arrangement. ... 198 

First layer — Dissection 199 

Trapezius 199 

Latissimus dorsi 199 

Second layer— Dissection. 201 

Levator anguli scapulas 201 

Rhomboideus minor et major 201 

Third layer — Dissection 201 

Serratus posticus superior et infe- 
rior 201,202 

Splenius capitis et colli , 202 

Fourth layer — Dissection 202 

Sacro-lumbalis — Longissimus dorsi 203 

Spinalis dorsi 203 

Cervical is ascendens — Trans versa- 

lis colli 204 

Trachelo-mastoideus — Complexus 204 

Fifth layer — Dissection 205 

Semi-spinalis dorsi et colli 205 

Rectus posticus, major et minor. . . 205 
Rectus lateralis — Obliquus inferior 

et superior 205 

Sixth layer — Dissection 205 

Multifidus spinas — Levatores cos- 

tarum 206 

Supra-spinalis — Inter-spinales .... 206 

Inter-transversales 206 

Actions 207 

Table of origins and insertions of the 

muscles of the back 208, 209 



XVI 



CONTENTS. 



Page 

Muscles of the thorax 210 

Intercostales externi et interni 210 

Triangularis sterni — Actions 211 

Muscles of the abdomen 211 

Dissection 211 

Obliquus externus 212 

Obliquus internus. 214 

Cremaster 214 

Transversalis 215 

Rectus 216 

Pyramidalis — Quadratus lumborum .216 

Psoas parvus 216 

Diaphragm 217 

Actions 218 

Muscles of the perineum 219 

Dissection 219 

Acceleratores urinae 220 

Erector penis 220 

Compressor urethra 220 

Transversus perinei 4 . . 221 

Sphincter ani externus et internus. . . 222 

Levator ani — Coccygeus 222 

Muscles of the female perineum .... 222 
Muscles of the upper extremity. . 223 

Anterior thoracic region. 224 

Dissection 225 

Pectoralis major et minor 225 

Subclavius — Actions 226 

Lateral thoracic region 226 

Serratus magnus — Actions 226 

Anterior scapular region 226 

Subscapularis 226 

Actions 227 

Posterior scapular region ' 227 

Supra-spinatus — Infra-spinatus 227 

Teres minor — Teres major 227, 228 

Actions 228 

Acromial region 228 

Deltoid — Actions 228 

Anterior humeral region — Dissection . . 229 

Coraco-brachialis — Biceps 229 

Brachialis anticus — Actions 230 

Posterior humeral region 230 

Triceps — Actions 231 

Anterior brachial region 231 

Superficial layer — Dissection 231 

Pronator radii teres 231 

Flexor carpi radialis 232 

Palmaris longus 232 

Flexor sublimis digitorum 232 

Flexor carpi ulnaris 233 

Deep layer — Dissection 233 

Flexor profundus digitorum 233 

Flexor longus pollicis 233 

Pronator quadratus — Actions .... 234 

Posterior brachial region 234 

Superficial layer — Dissection .... 234 

Supinator longus 234 

Extensor carpi radialis longior . . . 235 
Extensor carpi radialis brevior. . . 235 
Extensor communis digitorum. . . 235 
Extensor minimi digiti 236 



Page 
Extensor carpi ulnaris — Anconeus 236 

Deep layer — Dissection 236, 237 

Supinator brevis 237 

Extensor ossis metacarpi pollicis. . 237 
Extensor primi internodii pollicis. . 237 
Extensor secundi internodii pollicis 237 

Extensor indicis — Actions 238 

Muscles of the hand 238 

Radial region — Dissection 238 

Ulnar region — Dissection 239, 240 

Palmar region 240 

Actions 242 

Muscles of the lower extremity. 242 

Gluteal region — Dissection 243 

Gluteus maximus et medius 244 

Gluteus minimus 245 

Pyriformis 245 

Gemellus superior — Obturator inter- 
nus 245 

Gemellus inferior — Obturator exter- 
nus 246 

Quadratus femoris — Actions 246 

Anterior femoral region — Dissection . . . 246 
Tensor vaginae femoris — Sartorius. . . 247 

Rectus — Vastus externus 248 

Vastus internus — Crureus — Actions. 248 
Internal femoral region— Dissection . . . 249 

Iliacus internus 249 

Psoas magnus — Pectineus — Adduc- 
tor longus 249, 250 

Adductor brevis — Adductor magnus 

—Gracilis .'. 250, 251 

Actions 251 

Posterior femoral region — Dissection . . 251 

Biceps femoris 251 

Semi-tendinosus — Semi-membranosus 

— Actions 251 , 252 

Anterior tibial region 253 

Dissection 253 

Tibialis anticus 253 

Extensor longus digitorum 253 

Peroneus tertius — Extensor proprius 

pollicis 254 

Actions _ 254 

Posterior tibial region 254 

Superficial group — Dissection 254 

Gastrocnemius 255 

Plantaris — Soleus — Actions 255 

Deep layer — Dissection 255 

Popliteus — Flexor longus pollicis. 256 

Flexor longus digitorum 256 

Tibialis posticus 257 



Actions 



257 



Fibular region — Dissection 257 

Peroneus longus— Peroneus brevis 258 

Actions 25« 

Foot — Dorsal region 258 

Plantar region" 259 

First layer — Dissection \ 259 

Second layer — Dissection 261 

Third layer — Dissection \[ 261 

Fourth layer — Actions !...*. 262 



CONTENTS. 



XV11 



CHAPTER V. 



THE FASCIAE. 



Pajre 



-, Page 

Fascia lliaca 268 

Fascia pelvica 268 

Obturator fascia 269 

Superficial perineal fascia 269 



General anatomy 26°3 

Fascije of the head and neck 264 

Temporal fascia 264 

Cervical fascia 264 

Fascis of the trunk 265 Deep perineal fascia .77 .......'.'.'.'.'. 269 

Fasciae of the upper extremity ... 271 
Fasciae of the lower extremity. . . 272 

Fascia lata 272 

Femoral hernia 273 

Fascia of the leg 274 



Thoracic fascia 265 

Abdominal fascia 266 

Fascia transversalis 266 

Oblique inguinal hernia 266 

Congenital hernia 267 

Encysted hernia 267 ! Plantar fascia'?. .' '. .' ." . . ." .' ' .' " " ' * .' .' .' ] .' 274 

Direct inguinal hernia 268 ! 



CHAPTER VI. 



THE ARTERIES. 



n Page 

General anatomy of arteries 275 

Inosculations — Structure 276, 277 

Aorta .'278 

Table of branches 281 

Coronary arteries 281 

Arteria innominata 281 

Common carotid arteries 282 

External carotid artery 283 

Table of branches 284 

Superior thyroid artery 284 

Lingual artery. 285 

Facial artery 285 

Mastoid artery 287 

Occipital artery fm ;_ 287 

Posterior auricular artery 287 

Ascending pharyngeal artery 287 

Parotidean arteries 287 

Transverse facial artery 287 

Temporal artery 288 

Internal maxillary 288 

Internal carotid artery 291 

Ophthalmic artery 292 

Anterior cerebral artery 293 

Middle cerebral artery 294 

Subclavian artery 294 

Table of branches 296 

Vertebral artery 296 

Basilar artery 296 

Circle of Willis 7. . ". \ 297 

Thyroid axis 298 

Inferior thyroid artery 298 

Supra-scapular artery 298 

Posterior scapular 299 

Superficial cervicis . . . 299 

2* B 



Profundis cervicis 299 

Superior intercostal artery — Internal 

mammary ; branches 299 

Axillary artery 300 

Table of branches 301 

Brachial artery 303 

Radial artery 394 

Ulnar artery 306 

Thoracic aorta ; branches 308 

Abdominal aorta ; branches 309 

Phrenic arteries 309 

Cceliac axis ; 310 

Gastric artery 310 

Hepatic artery H ... _ 310 

Splenic artery 311 

Superior mesenteric artery 312 

Spermatic arteries 314 

Inferior mesenteric artery 315 

Renal arteries 315 

Lumbar arteries 315 

Sacra media 316 

Common iliac arteries 316 

Internal iliac artery 317 

Ischiatic 318 

Internal pudic artery 318 

External iliac artery 321 

Femoral artery 323 

Popliteal artery 326 

Anterior tibial artery 328 

Dorsalis pedis artery 329 

Posterior tibial artery 330 

Peroneal artery 331 

Plantar arteries 332 

Pulmonary artery # 334 



XV1I1 



CONTENTS. 



CHAPTER VII. 



THE VEINS. 



Page 

General anatomy 334 

Veins of the head and neck 33G 

Veins of the diploe 337 

Cerebral and cerebellar veins 338 

Sinuses of the dura mater 338 

Veins of the neck 341 

Veins of the upper extremity 342 

Veins of the lower extremity . . . .' 344 

Veins of the trunk 344 



Page 

Vense innominate 345 

Superior vena cava 345 

Iliac veins 345 

Inferior vena cava 346 

Azygos veins 348 

Vertebral and spinal veins 348 

Cardiac veins 349 

Portal system 349 

Pulmonary veins 351 



CHAPTER VIII 



THE LYMPHATICS. 



Page i 

General anatomy 351 I Lymphatics of the viscera. . 

Lymphatics of the head and neck 353 Lacteals 

Lymphatics of the upper extremity .... 354 j Thoracic duct 

Lymphatics of the lower extremity .... 355 Ductus lymphaticus dexter. 
Lymphatics of the trunk 356 j 



Pago 
357 
358 
359 
360 



CHAPTER IX. 



THE NERVOUS SYSTEM. 



Page 

General anatomy 361 

The brain 367 

Membranes of the encephalon 368 

Dura mater 369 

Arachnoid membrane 370 

Pia mater 37 1 

Cerebrum 372 

Lateral ventricles 373 

Fifth ventricle 376 

Fornix 378 

Thalami optici 378 

Third ventricle 378 

Corpora quadrigemina 379 

Pineal gland 379 

Fourth ventricle 380 

Lining membrane of the ventricle. . . 380 

Cerebellum 381 

Base of the brain 382 



Page 

Medulla oblongata 385 

Diverging fibres 38R 

Converging fibres; commissures 388 

Spinal cord 389 

Cranial nerves 392 

Spinal nerves 409 

Cervical plexus 411 

Brachial plexus 411 

Dorsal nerves 420 

Lumbar nerves 422 

Sacral nerves 426 

Sympathetic system 433 

Cranial ganglia 433 

Cervical ganglia 437 

Thoracic ganglia 440 

Lumbar ganglia 441 

Sacral ganglia 442 



CONTENTS. 



XIX 



CHAPTER X 



ORGANS OF SENSE. 



Pa fie 
Nose 442 

Nasal fossa 444 

Eyeball 445 

Sclerotic coat and cornea . 445 

Choroid coat; ciliary ligament; iris . 447 

Retina ; zonula ciliaris 449 

Humours 451 

Physiological observations 452 

Appendages of the eye 453 

Lachrymal apparatus 455 

Organ of hearing 456 

External ear ; pinna 456 

Meatus auditorius 457 



Pa S» 
Organ of hearing — continued. 

Tympanum 458 

Ossiculi auditus 458 

Muscles of the tympanum 459 

Internal ear 461 

Vestibule 462 

Semicircular canals — Cochlea 463 

Membranous labyrinth 465 

Organ of taste — Tongue 467 

Organ of touch — Skin 468 

Appendages of the skin — Nails 472 

Hairs — Sebiparous glands 474 

Sudoriparous glands 474 



CHAPTER XI. 

THE VISCERA. 



Page 

Thorax 475 

Heart 475 

Structure of the heart 482 

Organs of respiration and voice 485 

Larynx — Cartilages 485 

L'gaments 486 

Muscles 488 

Trachea and Bronchi 491 

Thy roid gland 492 

Lungs 492 

Pleurae 495 

Mediastinum 496 

Abdomen — Regions 496 

Peritoneum . . 497 

Alimentary canal 501 

Lips — Cheeks — Gums — Palate 502 

Tonsils — Fauces 503 

Salivary glands 503 

Pharynx 504 

Stomach 505 

Small intestine 506 

Large intestine 507 

Structure of the intestinal canal .... 509 



Page 

Abdomen — continued. 

Liver 515 

Gall-bladder 525 

Pancreas 526 

Spleen 526 

Supra-renal capsules 527 

Kidneys 528 

Pelvis j 532 

Bladder 532 

Prostate gland 534 

Vesiculae seminales 535 

Male organs of generation 536 

Penis 536 

Urethra 537 

Testes 541 

Female pelvis 544 

Bladder — Urethra 544 

Vagina 545 

Uterus 546 

Fallopian tubes 549 

Ovaries . 549 

External organs of generation 550 

Mammart glands 551 



CHAPTER XII. 



ANATOMY OF THE FCETUS. 



Page 

Osseous and ligamentous system 553 

Muscular system 553 

Vascular system , 553 

Foetal circulation 553 

Nervous system 555 

Organs of Sense — Eye — Ear — Nose. .. 555 

Thyroid gland 556 

Thymus gland 556 



Pace 

Foetal lungs. . .' 558 

Foetal heart 559 

Viscera of the abdomen 559 

Omphalo-mesenteric vessels 559 

Foetal liver 560 

Kidneys and supra-renal capsules . . . 560 

Viscera of the pelvis 560 

Testes — Descent 560 



TABLE OF ILLUSTRATIONS. 



Pigs. 

1. 

2. 
3. 

4. 

5. 

6. 

7. 

8. 

9. 
10. 
11. 
12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
21. 
22. 
23. 
24. 
25. 
26. 
27. 
28. 
29. 
30. 

31. 
32. 

33. 
34. 
35. 
36. 
37. 
38. 
39. 
40. 
41. 
42. 

43. 
44. 
45 



Page 

Vegetable nucleated cells 37 

Growth of cells 41 

Reproduction of cells 41 

Implantation of cells 41 

Transformation of cells 42 

/ Changes in formative cells of 

I an animal 42 

Id. of a vegetable 42 

Formation of fibres 42 

Minute structure of bone 44 

Id. id. id 45 

Development of bone 47 

Id. id 47 

Id. id. 47 

Cervical vertebra 51 

Atlas 51 

Axis 52 

Dorsal vertebra 53 

Lumbar vertebra 53 

Sacrum 57 

Occipital bone — External surface . 59 

Occipital bone — Internal surface . . 60 

Parietal bone — External surface . . 61 

Parietal bone — Internal surface. . . 62 

Frontal bone — External surface . . 63 

Frontal bone — Internal surface... 63 

Temporal bone — External surface. 64 

Temporal bone — Internal surface . 66 
Meatus auditorius externus and in- 

ternus, and tympanic bone 66 

Sphenoid bone — Superior surface . 69 
Sphenoid bone — Antero-inferior 

surface 70 

Ethmoid bone 73 

Superior maxillary bone 74 

Lachrymal bone .. . . 77 

Palate bone — Internal surface .... 78 

Palate bone — External surface ... 79 

Inferior maxillary bone 82 

Skull, anterior view 85 

Base of the skull ; internal view . . 85 

Base of the skull ; external view. . 87 
Nasal fossa with the turbinated 

bones 91 

Permanent teeth 92 

Temporary teeth 93 

Section of molar tooth 94 



Figs. g Page 

46. Capsule of temporary incisor 97 

47. Temporary tooth with capsule of 

permanent . 98 

48. Os hyoides 99 

49. Thorax 101 

50. Scapula 104 

51. Humerus 106 

52. Ulna and radius 108 

53. Bones of the carpus; posterior view 109 

54. Hand; anterior view Ill 

55. Os innominatum 114 

56. Female pelvis ; anterior view .... 117 

57. Femur; anterior view 119 

58. Femur ; posterior view 120 

59. Tibia and fibula; anterior view. . . 122 

60. Tibia and fibula ; posterior view. . 123 

61. Foot ; dorsal surface 125 

62. Foot ; plantar surface 128 

63. Articular cartilage 132 

64. Id. id 132 

65. Id. id 133 

66. Reticular cartilage 1 33 

67. Fibrous cartilage 133 

68. White fibrous tissue 134 

69. Yellow fibrous tissue 135 

70. Adipose tissue 136 

71. Epithelium of serous membrane. . 137 

72. Ligaments of the vertebra? and ribs ; 

anterior view 138 

73. Posterior common ligament 138 

74. Ligamenta subflava 139 

75. Ligaments of the atlas, axis, and 

occipital bone 140 

76. Id. ; posterior view 140 

77. Id. ; internal view 141 

78. Id. ; internal view 142 

79. Ligaments of the lower jaw ; ex- 

ternal view 143 

80. Id. ; internal view 143 

81. Id ; section 144 

82. Ligaments of the vertebral column 

and ribs 145 

83. Ligaments of the pelvis and hip joint 148 

84. Id. id. id.... 148 

85. Ligaments of the sternal end of the 

clavicle and costal cartilages. . . . 150 

86. Ligaments of the scapula and 

shoulder joint 151 

(xxi) 



XX11 



TABLE OF ILLUSTRATIONS. 



Figs. 
87. 

38. 
89. 
90. 
91. 
92. 
93. 
94. 
95. 

96. 

97. 

98. 

99. 
100. 
101. 
102. 
103. 
104. 
105. 
106. 
107. 
108. 
109. 

110. 
111. 
112. 
113. 
114. 

115. 
116. 

117. 

118. 
119. 
120. 

121. 
122. 

123. 

124. 

125. 

126. 
127. 
128. 
129. 

130. 

131. 

132. 

133. 



Page 
Ligaments of the elbow ; internal 

view 153 

Id. ; external view 153 

Radio-ulnar articulation 154 

Ligaments of the wrist and hand. 155 
Synovial membranes of the wrist. . 157 

Knee joint; anterior view 160 

Id. ; posterior view 161 

Knee joint ; internal view 161 

Id. ; reflexions of the synovial 

membrane 1 62 

Ankle joint; internal view 164 

Id. ; external view 164 

Id. ; posterior view 166 

Ligaments of the sole of the foot. . 167 

Minute structure of muscle 170 

Id. id 170 

Id. id 171 

Id. id 171 

Id. id 172 

Muscles of the face 174 

Tensor tarsi ... . 176 

Muscles of the orbit 176 

Pterygoid muscles 1 84 

Muscles of the neck; superficial 

and deep 1 86 

Muscles of the tongue 191 

Muscles of the pharynx 194 

M uscles of the soft palate 1 95 

Muscles of the prevertebral region 197 
Muscles of the back ; 1st, 2d, and 

3d layer 200 

Muscles of the back ; deep layer. . 203 
Muscles of the anterior aspect of 

the trunk 213 

Muscles of the lateral aspect of the 

trunk 215 

Diaphragm 218 

Muscles of the perineum 221 

Muscles of the anterior humeral re- 
gion ' 229 

Triceps extensor cubiti . 230 

Superficial layer of muscles of the 

anterior aspect of the fore-arm. . 231 
Deep layer of muscles of the ante- 
rior aspect of the fore-arm 234 

Superficial layer of muscles; poste- 
rior aspect of the fore-arm 235 

Deep layer ; posterior aspect of the 

fore-arm 237 

Muscles of the hand, anterior aspect 239 

Palmar interossei 241 

Dorsal interossei 241 

Muscles of the gluteal region, deep 

layer 244 

Muscles of the anterior and internal 

femoral region 247 

Muscles of the gluteal and posterior 

femoral region 252 

Muscles of the anterior tibial re- 
s' 011 253 

Muscles of the posterior tibial re- 
s'™ 255 



Figs. Page 

134. Muscles of the posterior tibial region, 

deep layer 256 

35. Dorsal interossii 259 

36. Muscles of the sole of the foot ; 1st 

layer 259 

37. Muscles of the sole of the foot; 2d 

layer 260 

38. Deep-seated muscles 261 

39. Plantar interossii 263 

40. Section of the neck, showing the 

distribution of the deep cervical 
fascia 265 

41. Transverse section of the pelvis, 

showing the distribution of the 
fasciae 269 

42. Deep perineal fascia x . . . 270 

43. Distribution of the deep perineal 

fascia ; side view 270 

44. Distribution of the fascia? at the 

femoral arch 273 

45. The great vessels of the chest .... 278 

46. Branches of the external carotid 

artery 284 

47. External carotid 289 

48. Branches of the subclavian artery. 296 

49. The circle of Willis 298 

50. Axillary and brachial arteries .... 301 

51. Arteries of the fore-arm — Radial , 

and ulnar •• 304 

52. Branches of the abdominal aorta. . 310 

53. Cceliac axis with its branches. . . . 312 
54^ The superior mesenteric artery . . . 313 

55. The inferior mesenteric artery. . . . 314 

56. The internal iliac artery with its 

branches . . . 317 

57. The arteries of the perineum 319 

58. The femoral artery with its branches 323 

59. The anterior tibial artery 328 

60.' Posterior tibial and peroneal artery 330 

61. Arteries of the sole of the foot .... 332 

62. Sinuses of the dura mater 339 

63. Sinuses of the base of the skull. . . 340 

64. Veins and nerves of the bend of the 

elbow 342 

65. Veins of the trunk and neck 346 

66. The portal vein 350 

67. The thoracic duct 360 

68. Minute structure of nerve 363 

69. The centrum ovale majus and cor- 

pus callosum 373 

70. The lateral ventricles of the cere- 

brum 374 

71. Longitudinal section of the brain. . 377 

72. Base of the brain 384 

73. Distribution of the fibres of the brain 387 

74. Sections of the spinal marrow .... 391 

75. Sections of the spinal cord 392 

76. The olfactory nerve 393 

77. Origin of the optic and fourth nerves 394 

78. The isthmus encephali, showing the 

thalamus opticus, corpora quadri- 
gemina, pons Varolii, and medulla 
oblongata 394 



TABLE OF ILLUSTRATIONS. 



XX111 



Fig*. Pa«e 

179. Third, 4th, and 5th pair of nerves 396 

180. Trifacial or fifth nerve 397 

181. Portio mollis of 7th pair 401 

182. Facial ami cervical nerves 403 

183. Eighth pair of nerves 406 

184. Hypoglossal or ninth nerve 408 

185. Part of the cervical portion of the 

spinal cord 410 

186. Axillary plexus and nerves of the 

upper extremity 414 

187. Nerves of front of fore-arm 417 

188. Nerves of back of fore-arm 418 

189. Lumbar and sacral plexus, with the 

nerves of the lower extremity. . . 422 

190. Anterior crural nerve 424 

191. Branches of ischiatic plexus 427 

192. id. popliteal nerve 430 

193. Posterior tibial nerve 430 

194. Nerves of sole of foot 431 

195. Anterior tibial nerve 432 

196. The cranial ganglia of the sympa- 

thetic nerve 434 

197. Great sympathetic 439 

198. Fibro-cartilages of the nose 443 

199. Longitudinal section of the globe 

of the eye 446 

200. Venae vorticosse of choroid coat . . . 448 

201. A transverse section of the globe of 

the eye . . . 449 

202. Another transverse section of the 

globe of the eye 449 

203. Auxiliary parts of eye 453 

204. A diagram of the ear 458 

205. Anatomy of the cochlea 464 

206. Osseous and membranous labyrinth 

of the ear 464 

207. Papillae of tongue 467 

208. Anatomy of the skin 469 

209. Development of epidermis 470 

210. Anatomy of the skin 473 

211. The heart 476 

212. Anatomy of the heart, right side . . 478 



Figs. Pape 

213. Anatomy of the heart, left side . . . 482 

214. Ligaments of the larynx 487 

215. Muscles of the larynx 488 

216. Id. id 489 

217. Anatomy of the lungs and heart. . 493 

2 1 8. Viscera of abdomen 497 

2 1 9. The peritoneum 498 

220. The pharynx 505 

221. Anatomy of the stomach and duo- 

denum 506 

222. Caecum and appendix 508 

223. Section of anus 510 

224. Peyer's glands 513 

225. Section of parietes of anus 514 

226. The liver; its upper surface 516 

227. The liver; its under surface 517 

228. Lobules of the liver 519 

229. Id. id 519 

230. Section of superficial lobules 520 

231. Id. id 521 

232. Section of the kidney 529 

233. Plan of the renal circulation 531 

234. A side view of the viscera of the 

male pelvis 533 

235. A posterior view of the bladder and 

vesiculse seminales 535 

236. Anatomy of the urethra 538 

237. Prostatic urethra 539 

238. Transverse section of the testicle. . 541 

239. Anatomy of the testis 543 

240. Injected testis 544 

241. A side view of the viscera of the 

female pelvis 545 

242. Uterus and Fallopian tubes 546 

243. Section of uterus 547 

244. Female external organs of genera- 

tion 550 

245. Foetal circulation 554 

246. Section of the thymus gland 557 

247. Ducts of the thymus gland 557 

248-9. Descent of the testis in the foetus 561 



SYSTEM OF HUMAN ANATOMY. 



CHAPTER I. 

INTRODUCTORY. 

BY THE EDITOE. 



Anatomy (derived from avars/jivsiv, to dissect) is the science which 
teaches the structure and relation of the different parts of an organized 
body. Organized bodies are divided into animal and vegetable ; hence 
we have animal and vegetable anatomy, the latter being closely allied to 
botany. 

An organized body consists of an assemblage of parts called organs, 
which have a mutual relation to, and dependence upon each other ; each 
doing its part to sustain the organism which they compose. The descrip- 
tion of the form, colour and position of these organs is the province of 
special anatomy ; whilst their relations to each other, and the knowledge 
of the number and arrangement of organs in particular parts, constitutes 
regional or topographical anatomy, which, when taught with reference, to 
surgical operations, is usually designated by the title of surgical anatomy. 
When these organs are carefully examined, they are found to consist of a 
number of different structures which serve to build up and constitute 
them. These are called tissues, and are either general, existing in all the 
organs, or special and peculiar, and found only in certain of them, giving 
them their appropriate characters. The knowledge of tissues, their form, 
colours, constituents, origin and uses, constitutes histology ; which, com- 
mencing with Bichat in 1790, has now attained such an extent and im- 
portance as to constitute almost a new science, and to correct and bring 
nearer to perfection the hypotheses of its sister science, physiology. 

An animal body or organism consists of solids, which differ in density 
and hardness, in consequence of being more or less mingled with and di- 
luted by the fluids which permeate them. 

By the agency of chemistry we may separate both solids and fluids into 
proximate and ultimate elements, and hope by this means to obtain a 
more intimate acquaintance with their structure and use ; but if this is 
done with the masses as is usual in chemical analyses, and not upon the 
tissues separated from each other by the aid of the microscope, it will 
confer upon us about as much real and useful information, as the analysis 
which a scientific but witty English chemist once made of a whole mouse. 

The principal ultimate elements of an animal body obtained by the pro- 
cesses of chemical analysis are — 

Oxygen, hydrogen, carbon, and nitrogen, which form almost the whole 
bulk of the fluids and soft solids ; but to these must be added a number 

C (33) 



34 HISTOLOGY. 

of others, which, although they exist in smaller proportions, still form im- 
portant constituents of peculiar tissues. Thus we find — 

Lime, or its base, calcium, combined with the carbonic or phosphoric 
acids, in the bones and teeth. 

Magnesia, in the sebaceous matter of the skin. 

Alumina, in the enamel of the teeth ; 

And iron, in the black pigment in various parts. 

The additional elements thus brought into the organism may be enume- 
rated as follows : 

Metallic bases of earths. — Calcium, magnesium, silicium, aluminum. 
Metallic bases of alkalies. — Potassium., sodium. 
Phosphorus, sulphur, chlorine, and fluorine. 
Metals. — Iron, manganese, titanium, arsenic, and copper. 
Almost all of these elements exist compounded in either the binary or 
ternary form. 

The binary compounds are — 

Water, found universally consisting of HO. 
Carbonic acid, found in blood, urine, sweat. 

Carbonates, or salts of carbonic acid : — 

Carbonate of soda, in serum, bile, mucus, sweat, saliva, tears, carti- 
lage, &c. 

Carbonate of ammonia, in the amniotic liquor, probably derived from 
the urine of the foetus. 

Carbonate of lime, in cartilage, bone, and the teeth. 

Carbonate of magnesia, in the sebaceous matter of the skin. 

Salts of phosphoric acid : — 

Phosphate of soda, in serum, saliva, sweat, bones, muscles, &c. 

Phosphate of lime, in bones, teeth, cartilage, and the sandy concretions 
of the pineal gland. 

Phosphate of soda and ammonia, in urine and blood; but probably only 
for the purpose of being excreted or thrown ofT as unfit to constitute a 
part of an any&ial body. 

Phosphate of iron, in blood, gastric juice, and urine. 

Chlorine and its compounds : — 

Hydrochloric acid, in gastric juice, and in the fluid of the caecum. 
Chloride of sodium, in blood, brain, muscle, bone, cartilage, dentine, 
and pigment. 

Chloride of potassium, in blood, gastric juice, milk, saliva. 
Chloride of ammonium, in sweat, gastric juice. 
Chloride of calcium, in gastric juice. 

Sulphuric acid and its compounds : — - 

Sulphate of potassa, in urine, gastric juice, and cartilage. 

Sulphate of soda, in sweat, bile, and cartilage. 

Sulphate of lime, in bile, hair, and cuticle. 

Sulpho-cyanide of potassa, in the saliva. 

Fluoride of calcium, in the enamel. 

Silica and oxide of manganese, in the hair. 

Alumina, in the enamel. 



HISTOLOfiY. 35 

Oxide of iron, in blood, black pigment, lens, and hair. 

Oxide of titanium, in the capsular renales. 

Ammonia and cyanogen only exist in excreted liquids, and conse- 
quently do not appear fit to form any part of an organism, one consisting 
of NH and the other of CH ; their elements may only have united 
for the purpose of finding a ready exit from the body through the emunc- 
tories. 

Chemistry and physiology have both failed to detect the mode in 
which the elements of an animal body form themselves into the ternary 
and quaternary compounds which are found or supposed to exist in them, 
and much confusion and uncertainty still prevail in regard to their compo- 
sition and the part they play in the animal organization. Almost all of 
these compounds contain nitrogen, in addition to the carbon, oxygen and 
hydrogen found in them ; and some of them are exactly alike in their ele- 
mentary chemical constitution, although differing in a remarkable manner 
in their sensible characteristics. Those ternary or quaternary compounds 
which contain nitrogen are prone to rapid putrescence, and have received 
the generic name of nitrosenized substances. 

I. Nitrogenized substances. — Perhaps the best mode of explain- 
ing these compounds is to admit the existence of protein, which is 
described by Mulder, and is so called because, itself a primary sub- 
stance, it originates so many dissimilar substances. It consists of C 40 
H 3] N 5 12 . By imagining it to unite with small proportions of either 
sulphur or phosphorus, or both, it may be said to form a number of ni- 
trogenized bodies. When in the moist state, protein is said to be gelatin- 
ous, and when dried, brittle, and of a brownish colour. It is inodorous 
and tasteless, insoluble in water, alcohol, or ether, but easily dissolved by 
all the acids in a dilute state. 

The substances formed by it are — 

1st. Albumen (Pr 10 + PS 2 ). This substance is exceedingly common 
in the animal economy, and a good example of it is presented in the 
white of an egg, which is nearly pure albumen. It forms an admirable 
matrix or blastema for the generation of cells, and the consequent forma- 
tion of tissues. When dry, albumen is solid, brittle, and of an amber 
yellow colour. It is soluble in water, coagulable by heat, alcohol and 
acids, and forms insoluble compounds with tannin, sugar of lead, and 
corrosive sublimate. 

Very nearly resembling albumen in many of its properties is — 

2d. Fibiin (Pr ]0 -f PS). This, however, possesses the power of coagu- 
lating, when removed from the body of a living animal, in from three to 
seven minutes, into a delicate rete or net-work. It is most readily ob- 
tained from blood, where it exists in solution, by whisking it with a bundle 
of twigs, which hastens its coagulation, and causes it to adhere to the 
twigs. When well washed with running water it presents a semi-solid 
condition, a dull yellowish colour, and scarcely an appreciable odour. 
Fibrin, in a coagulated state, forms almost the whole bulk of the muscles. 

3d. Casein (Pr 10 -f- S). This substance is abundantly found in milk, 
and constitutes, when dried, cheese. It is soluble in water, and coagu- 
lated by alcohol, acids, and the stomach of any of the mammalia. Be- 



36 HISTOLOGY. 

sides forming a constituent of milk, casein is found in blood, saliva, bile, 
and the lens of the eye. 

4th. Pepsin. This substance was discovered by Schwann, and analysed 
by Vogel, who found it to be composed of C^ H 32 N 8 O 10 . It is so 
much like albumen that it is difficult to discover a distinction between 
them. It is found in the gastric glands. 

5th. Globulin (Pr 15 + S) exists in the blood corpuscles; very like albu- 
men. 

6th. Spermatin is found in semen ; probably fibrin, altered and filled 

with living forms. 

7th. Mucus consists of globules floating in a clear fluid, the constitution 
of each being different. 

8th. Keratin (Pr S 2 ). The product of the analysis of hair, cuticle, &c. 

9th. Salivin. Found only in the saliva. 

Besides the protein compounds thus enumerated, we have the extractive 
matter, obtained by either water or alcohol from muscular flesh. 

The watery extract is called osmazome, is highly volatile, gives the 
taste and odour to soups and roast meats, and is no doubt a product of 
the treatment of the meat, or a new combination of the animal elements 
occurring during the effort to procure it. 

Gelatine is another substance obtained from portions of the animal 
body, and differs according to the tissue which furnishes it. Thus ten- 
dons, ligaments and bone furnish colla, or glue, which consists of C 52 
H 40 N 8 O20 ; whilst the cartilages and the cornea furnish chondrin, the 
composition of which is N 32 H 26 N 4 14 . 

Hematin is found in C^ H^ N 3 6 united with a little iron, which is 
not essential to its composition or existence. 

A number of principles have been described as existing in the hepatic- 
secretion or bile, but much research is yet necessary to clear up the con- 
fusion which exist in writings with regard to them. They may be enu- 
merated : — Bilin, fellinic acid, cholinic acid, taurin, dy sly sin, cholepyrrhin, 
biliphcein, biliverdin, bilifulvin, cholesterin, oleate, mangarate, and stearate 
of soda, chloride of sodium, sulphate, phosphate, and lactate of soda, and 
phosphate of lime. 

Urea and uric acid, found in the urine, should not be considered as 
constituent parts of an animal, but as elements combined in a particular 
way for the purpose of being excreted. 

II. The non-nitrogenized compounds, found in the bodies or secretions 
of animals, are not numerous. When milk is dried, two-fifths of its solid 
contents consist of a peculiar sugar, called saccharum laciis, and composed 
of Cr, H 4 4 + HO. It crystallizes in four-sided prisms, and has a sp. gr. 
of 1.543. 

It also contains an acid called lactic (C 6 H 5 5 ), common in all the 
fluids and secretions of the body, and united in them with either potash, 
soda, ammonia, lime, or magnesia. 

Fat consists of cells held together by areolar tissue and vessels, and is 
found by the chemists to contain glycerin, stearic acid, margaric acid, and 
elaic acid, all of which are destitute of nitrogen. 

The solidity of the fat of an animal depends upon the proportion of the 
above ingredients ; thus, when stearic acid preponderates, the fat is solid, 
and when elaic, fluid. 



HISTOLOGY. 



37 



Fig. 1* 



OF THE TI SSUES. 

The solids of an animal body have been divided into tissues, any one 
of which presents the same characteristics, no matter in what portion of 
the body it is found. The tissues may be further divided into simple and 
compound tissues ; meaning by compound those which consist of two or 
more simple or elementary tissues mixed together in a definite and regular 
manner. As an instance of this we may mention fibro-cartilage, which 
consists of a net-work of white fibrous tissue, having its meshes or inter- 
stices filJed up by a cartilaginous deposit. 

The simplest form of animal organism is 
the nucleated corpuscle or cell, which is a 
little vesicle or bag, containing a fluid in its 
early stage, and a granular body called a 
nucleus, attached to some portion of the cell 
wall. This nucleus occasionally presents 
one or two distinct corpuscles in its sub- 
stance, which when found are called nucle- 
oli, and which possibly are the germs of new 
cells. 

Every portion of the animal organism is 
formed by these cells, and as the body is undergoing constant repro- 
duction and decay, they are found in various stages of development 
at any time in the life of an animal. 




DIVISION OF THE TISSUES, 



The animal organism may be divided into simple, or non-metamor- 
phosed forms, and compound, or metamorphosed forms of animal matter. 
They are presented in the following tabular form : 



1. Simple Forms: — 

1. Nucleated cells, 

2. Corpuscles, 



1. Formative, producing solids [durable). 

2. Secreting, producing fluids (evanescent). 

1. Of the blood, 

2. Of the lymph, 

3. Of the chyle. 



2. Compound Forms : — 

tissues produced by the metamorphosis of cells. They are divided 
into simple and compound tissues. 

Simple Tissues : 

1. Simple membrane, 

2. Pigmentary membrane, 

3. Tesselated epithelium, 

4. Cylindroid epithelium, 

5. Ciliated epithelium, 

6. Aggregated epithelium. 
White fibrous tissue {indastic). 



1. Epithelial tissue, 
presenting several < 
varieties. 



3. Yellow fibrous tissue {elastic). 

* A group of vegetable cells. J. Nucleus. 2. Nucleoli in nucleus. 



38 HISTOLOGY. 



4. Cartilaginous tissue. 



5. Osseous tissue. 

6. Petrous tissue. 

Compound Tissues : 

n __ . _. .. CI. Striped muscular fibre, 

1.. Muscular fibrous tissue, j % Unstriped muscu lar fibre. 

2. Nerve-fibrous tissue. 
Binary Tissues, formed of two simple tissues: 

1. Areolar tissue, constituted by the white and yellow fibrous 

tissues intermixed. 

2. Fibro- cartilage, constituted by cartilage and white fibrous 

tissue intermixed. 

A certain difference exists between the simple corpuscles and nucleated 
cells. The corpuscles of the blood, for instance (in the mammalia), are 
destitute of a nucleus, and are persistent ; whereas a nucleated cell is 
always in a state of progression, either producing a fluid or undergoing a 
transformation. 

The 1st variety of epithelium is found where there is a necessity for 
transparency, as in the capsule of the lens and the posterior layer of the 
cornea. The membrane in this case may be produced by the develop- 
ment of a very large cell and the collapse of its walls, so as to cover the 
whole area, thus constituting a duplicate lamina. 

The 2d variety is formed of hexagonal plates, adhering to each other 
and containing a form of carbon ; it is found in the eye, in the lung, and 
mixed with the cuticle and hair of the negro. 

The 3d variety constitutes the free surface of many membranes, as the 
skin, the mucous and serous ; it may be found in a single lamina, forming 
a pavement of nucleated cells, flattened and adhering by their edges ; or it 
may form superimposed laminae, the exterior of which is constantly peeling 
off*, and the interior as constantly reproducing new cells to keep up the 
covering. This is the case in the cuticle, and in the mucous membranes 
of the mouth, oesophagus, rectum, &c. 

The 4th variety exists in mucous membranes, and consists of conoidal 
nucleated cells, very firmly paved together. 

The 5th variety differs only from the last in having the base furnished 
with vibratile ciliae, which diffuse the secretion, moistening the surface by 
their constant motion. This kind of epithelium occurs in mucous and 
serous membranes, w 7 here the surfaces cannot come together and rub 
against each other, as in the ventricles of the brain, the trachea, &c. 

Nails, hairs, and horny excrescences, are manifestly modifications of 
epithelium, and are hence included in the enumeration as constituting the 
sixth variety of that tissue. 

The White fibrous tissue exists in ligaments and tendons, and consti- 
tutes the principal part of the derm or cutis vera. It is inelastic and in- 
extensible. 

The Yellow fibrous tissue is found in the ligamenta flava of the spine, 
in the middle coat of the arterial system, and in the skin, mixed with the 
white fibrous element. 

The Cartilaginous tissue constitutes the cartilage of the ribs, and the 



HISTOLOGY. 39 

articular coverings for the ends of the bones. It is also found existing 
transitorily in the process of osteo-genesis . 

The Osseous tissue constitutes the skeleton, and, with some modification, 
the ivory of the teeth or dentine. 

The Petrous tissue presents the extreme of departure from the animal 
organization, consisting almost entirely of crystals, which are chiefly com- 
posed of* phosphate of Time. It is found in the enamel of the teeth, in the 
otoconites, and in the concretions of the pineal gland. 

The Muscular fibrous tissue constitutes the apparatus of motion, and is 
divided into two distinct varieties, — striped, or the muscular fibre of ani- 
mal life ; and wistriped, or the muscular fibre of organic life : — the former 
acting in obedience to the will, and the latter being wholly independent 
of it. 

The Nerve fibre is the conducting portion of the nervous system, and is 
like the muscular compound, being formed of two distinct substances, the 
one containing and the other contained. 

The Binary tissues are merely the intermixture or co-existence of two 
elementary tissues, the proportions of which vary according to the exigen- 
cies of the part of the body in which they are found. 

The grey or vesicular nervous matter consists of secreting cells, which 
disappear and are reproduced. 

Adipose tissue consists also of secreting cells, which retain their con- 
tents under certain circumstances for a great length of time, while under 
others they rapidly disappear. 

The vascular, mucous, and serous tissues of older writers, consist of 
aggregations of areolar, muscular, and epithelial tissues, variously modified. 

PROPERTIES OF THE TISSUES. 

The Chemical Properties have been given in the early portion of 
this chapter. 

physical properties of the tissues. 

The tissues, like other forms of matter, possess certain physical proper- 
ties, such as colour, consistency, and density, which it is necessary to 
describe under their respective heads. One property, however, is enjoyed 
by every tissue, and this seems to play a most important part in the main- 
tenance of the functions of life. I allude to the transudation of the solids 
by the fluids, which is known by the title of endosmosis and exosmosis, 
names by which the process was designated by Dutrochet, its discoverer. 
All the tissues contain a certain quantity of water, and in some cases this 
amounts to four-fifths of their weight, as may be proved by drying them ; 
and this water is essential, not only to their vitality, but confers upon them 
their organic properties — pliability and elasticity. As the tissues imbibe 
water in certain quantity, it becomes a subject of study to discover the 
manner by which the quantity may be increased. It is well understood 
how pressure from without would produce this effect, but even this would 
be aided by the natural tendency to imbibe and retain an additional quan- 
tity of water under favourable circumstances, which is strongly exhibited 
by the softer tissues. Such a tissue saturated with water placed in contact 
with another tissue or a fluid having a higher affinity for water than it has, 
will part with its superabundance, and if not supplied from behind will 



40 HISTOLOGY. 

even part with a portion of that which is essential to its normal condition. 
If, however, it is supplied from the other side, it will continue to supply 
the imbibing fluid and receive more from behind. Thus a current will be 
established from the water on one side of the tissue to the fluid having a 
high affinity for it on the other ; but this is not all: for the fluid alluded 
to, not content with absorbing all the water which the animal tissue sup- 
plies it with, in its turn transudes the tissue to get at and mix with the 
water on the other side, and thus a counter-current is set up in an oppo- 
site direction, which is slower, however, than the former one. These are 
the currents which are termed endosmotic and exosmotic, and which con- 
tinue until the difference between the two liquids ceases, and they are 
equally saturated by each other. 

VITAL PROPERTIES. 

The most prominent vital property possessed by the tissues is the power 
of assimilation, or of appropriating to themselves such of the organizable 
substances presented to them as may suit their purposes. This power is 
supposed to be partly due to chemical affinity, and partly to vital affinity. 
It is most probable, however, that future researches will prove that the 
power of assimilating is subject to the ordinary chemical laws, but under 
modifying circumstances, which can only exist in a living body or tissue. 

To this may be added the power of reproducing, in its appropriate 1 
place, a new portion of a tissue, when injured or destroyed. 

Another property which is essentially vital is contractility — a phenome- 
non which is made manifest by the visible shrinking or contraction of a 
living tissue when irritated, either by mechanical or chemical stimuli. 
The muscular tissue exhibits this property in the highest degree. This 
contractility must be distinguished from the permanent contraction or 
crispation which a part suffers when exposed to a high temperature. 

A third vital property is sensibility, which, how r ever, requires that the 
tissues shall be united so as to form a continuous line from the part mani- 
festing it to the brain. This property is enjoyed in very different degrees 
by the different tissues, and constitutes an important distinction between 
them, depending upon the presence and number of nerve-fibres mixed 
with the tissue. 

DEVELOPMENT OF THE TISSUES. 

The tissues, however diversified in form, are all developed ,in the fol- 
lowing manner : ; 

A nucleated cell attracts from the blastema in which it is formed, or 
from the capillary vessels contiguous to it, certain elements which combine 
in its interior, and either form a portion of the animal body, — in which 
case the remains of the cell, and particularly its nucleus, continue to exist 
in the part, and can be made evident by chemical agents under the 
microscope, — or they become filled with a fluid, and bursting when ripe, 
and mixing and flowing along with their former contents, are discharged 
into a tube or duct, and constitute a secretion or a secreted fluid. The only 
difference between these two kinds of cell, which we designate by the terms 
formative and secreting, is that the former secrete a solid or semi-solid, 
which remains in the body with the debris of the cell for an appreciable 
period of time, whilst the latter secrete a fluid which escapes from the 



HISTOLOGY. 



41 



body with the remains of the cell which gave it birth. Each of these 
little bodies may be compared to a laboratory, which receives from the 
surrounding matter the elements which it requires, and combines them so 
as to produce a desired result. 

The various modifications and aggregations of these cells constitute the 
varied forms of animal and vegetable tissues. 



DEVELOPMENT OF CELLS. 

A cell originates in a mass of soft or liquid matter, which is organizable 
or capable of being organized. In other words, a liquid formed of a com- 
bination of elements fitted to produce an organized structure. This sub- 
stance is called "blastema." As an example, we may take the liquor 
sanguinis or the blood, excluding its globules, which in a fully formed 
animal is a universally diffused blastema. 

A minute point (see Fig. 2) arises in this blastema, which increases in 

size ; a transparent wall is seen to 

spring up like a watch-glass from one 

side of the granule, which swells up 

more and more until the granule is seen 

to exist in, and adhere to the side of the 

cell wall. When thus formed, we have 

the cell wall with its fluid contents, and the granule or nucleus, which 

may by this time have developed several new granules or nucleoli in its 

interior. 




MULTIPLICATION OF CELLS. 

Cells are multiplied in several modes : 

1st. By repetition, i. e., of the development from a blastema, as ex- 
plained. 

2d. By the development of new nuclei and cells within the parent cell- 
wall (see fig. 3). 



Fig. 3.t 



Fig. 4.* 





3d. By the development of new cells from the parietes of pre-existing 
ones. This is shown in fig. 4. 



TRANSFORMATION OF CELLS. 

1st. Cells may lose their fluid contents, and their walls collapsing until 
they come in contact and adhere, they form simple, membranous, and 
transparent discs. 

* Development of cell from blastema. On the left is seen the corpuscle which be- 
comes the nucleus ; on the right the complete nucleated cell, 
f Development of new cells within the parent cell. 
$ Development of new cells from the outer wall of pre-existing cells. 



42 



HISTOLOGY. 



2d. Cells may elongate so as to form tubes or solid rods ; in the former 
case they adhere by their ends to neighbouring cells, and their cavities 
mutually open into each other, thus forming a vessel : in the latter the 

fluid content is lost, and a rod or 
Fl &- 5 * fibre is the result. Curious forms 

are produced by a modification of 

W^~~ ~~\^ ( ^he sarae l aw j as exemplified in 

fig. 5. 

3d. Solid deposits may occur 
within the cell wall, obliterating its 
cavity. 

4th. The same thing may occur 
in the blastema, exterior to the cell 
walls, and thus a solid will result. 
Examples of the third and fourth 
kind occur in the formation of cartilage, as is illustrated in the accompa- 
nying cuts. 





6.f 



Fig. 7.f 



Fig. 8.f 



Fig. 9.t 






Fig. 10.§ 




5th. A curious modification of development 
occurs in the feathers of birds, where a nucleated 
cell elongates and becomes filled with fibres ; the 

a cell wall is rubbed off by attrition, and the fibres 
are thus uncovered and exposed. See fig. 10, 
a, 6, c. 

b Finally, it is believed by some that the blastema 
may form a simple membrane or fibre without the 
intervention of a cell, although this is by no means 
proved. 



* Curious forms of cell transformation usually found in abnormal deposits. 

■j- Development of cartilage. 

\ Deposit in layers of lignin in the interior of vegetable cells. 

§ Mode of formation of the feathers of a bird in the interior of a nucleated cell. 



CLASSES OF BONE. 43 

CHAPTER II. 

OSTEOLOGY. 

The bones are the organs of support to the animal frame ; they give 
firmness and strength to the entire fabric, afford points of connection to 
the numerous muscles, and bestow individual character upon the body. 
In the limbs they are hollow cylinders, admirably calculated by their con- 
formation and structure to resist violence and support weight. In the 
trunk and head, they are flattened and arched, to protect cavities and 
provide an extensive surface for attachment. In some situations they 
present projections of variable length, which serve as levers ; and in others 
are grooved into smooth surfaces, which act as pulleys for the passage of 
tendons. Moreover, besides supplying strength and solidity, they are 
equally adapted, by their numerous divisions and mutual apposition, to 
fulfil every movement which may tend to the preservation of the creature, 
or be conducive to his welfare. 

According to the latest analysis by Berzelius, bone is composed of about 
one-third of animal substance, which is almost completely reducible to 
gelatine by boiling, and of two-thirds of earthy and alkaline salts. The 
special constituents of bone are present in the following proportions : — 

Cartilage 32-17 parts. 

Blood-vessels 1*13 

Phosphate of lime 51-04 

Carbonate of lime 11-30 

Fluateoflime 2-00 

Phosphate of magnesia 1*16 

Soda, chloride of sodium . 1-20 



100-00 
Bones are divisible into three classes: — Long, flat, and irregular. 
The Long bones are found principally in the limbs, and consist of a 
shaft and two extremities. The shaft is cylindrical or prismoid in form, 
dense and hard in texture, and hollowed in the interior into a medullary 
canal. The extremities are broad and expanded, to articulate with ad- 
joining bones ; and cellular or cancellous in internal structure. Upon the 
exterior of the bone are processes and rough surfaces for the attachment 
of muscles, and foramina for the transmission of vessels and nerves. The 
character of long bones is, therefore, their general type of structure and 
their divisibility into a central portion and extremities, and not so much 
their length ; for there are some long bones, as the second phalanges of 
the toes, which are less than a quarter of an inch in length, and almost 
equal, and in some instances exceed, in breadth their longitudinal axis. 
The long bones are, the clavicle, humerus, radius and ulna, femur, tibia 
and fibula, metacarpal bones, metatarsal, phalanges, and ribs. 

Flat bones are composed of two layers of dense bone with an interme- 
diate cellular structure, and are divisible into surfaces, borders, angles, and 
processes. They are adapted to inclose cavities ; have processes upon 
their surface for the attachment of muscles ; and are perforated by foramina, 
for the passage of nutrient vessels to their cells, and for the transmission 



44 



STRUCTURE OF BONE. 



of vessels and nerves. They articulate with long bones by means of smooth 
surfaces plated with cartilage, and with each other either by fibrous tissue, 
as at the symphysis pubis ; or by suture, as in the bones of the skull. The 
two condensed layers of the bones of the skull are named tables ; and the 
intermediate cellular structure, diplbe. The flat bones are the occipital, 
parietal, frontal, nasal, lachrymal, vomer, sternum, scapulae, and ossa 
innominata. 

The Irregular bones include all that remain after the long and the flat 
bones have been selected. They are essentially irregular in their form, in 
some parts flat, in others short and thick. In preceding editions of this 
work the short and thick bones were made a separate class, under the 
name of short bones. This subdivision has been found to be disadvan- 
tageous, besides being arbitrary, and is, therefore, now omitted. Irregular 
bones are constructed on the same general principles with other bones ; 
they have an exterior dense, and an interior more or less cellular. The 
bones of this class are, the temporal, sphenoid, ethmoid, superior maxil- 
lary, inferior maxillary, palate, inferior turbinated, hyoid, vertebrae, sacrum, 
coccyx, carpal and tarsal bones, and sesamoid bones, including the patellae. 

Structure of Bone. — Bone is a dense, compact, and homogeneous sub- 
stance (basis substance) filled with minute cells (corpuscles of Purkinje), 
which are scattered numerously through its structure. The basis substance 
of bone is subfibrous and obscurely lamellated, the lamellae being concentric 
in long and parallel in flat bones ; it is traversed in all directions, but es- 
pecially in the longitudinal axis, by branching and inosculating canals 



Fig. 11* 




canals), which give 
vessels and nerves. 



(Haversian 
passage to 

and in certain situations the la- 
mellae separate from each other, 
and leave between them areolar 
spaces (cancelli) of various mag- 
nitude. The lamellae have an 
average diameter of ^^ of an 
inch, and, besides constituting the 
general structure of the basis sub- 
stance, are collected concentrically 
around the Haversian canals, and 
form boundaries to those canals of 
about 257 of an inch in thickness. 
The number of lamellae surround- 
ing each Haversian canal is com- 
monly ten or fifteen, and the di- 
ameters of the canals have a me- 
dium average of ^ of an inch. The cancelli of bone, like its compact 
substance, have walls which are composed of lamellae ; and, such is the 

* Minute structure of bone, drawn with the microscope from nature, by Bagg. Mag- 
nified 300 diameters. 1. One of the Haversian "canals surrounded by its concentric 
lamellre. The corpuscles are seen between the lamellae; but the calcigerous tubuli are 
omitted. 2. An Haversian canal with its concentric lamellae, Purkinjean corpuscles, 
and tubuli. 3. The area of one of the canals. 4, 4. Direction of the lamella? of the 
great medullary canal. Between the lamella? at the upper part of the figure sevenl 
very long corpuscles with their tubuli are seen. In the lower part of the figure' the out- 
bids ol three other canals are given, in order to show their form and mode of 'arrant 
meiit in the entire bone. p 



DEVELOPMENT OF BONE. 



45 



similarity in structure of the parts of a bone, that the entire bone may be 
compared to an Haversian canal of which the medullary cavity is the mag- 
nified channel ; and the Haversian canals may be likened to elongated and 
ramified cancelli. The Haversian canals are smallest near the surface 
of a bone, and largest near its centre, where they gradually merge into 
cancelli; by the frequent communications of their branches they form a 
coarse network in the basis substance. 

Fig. 12 * 




The cells of bone, or corpuscles of Purkinje, are thickly disseminated 
through the basis substance ; they are irregular in size and form, give 
off numerous minute branching tubuli, which radiate from all parts of 
their circumference, and in the dried state of the bone contain merely 
the remains of membranous cells and some calcareous salts. f In the 
living bone, the cells and their tubuli are probably filled with a nutritive 
fluid holding calcareous salts in solution. The form of the cells is oval 
or round, and more or less flattened, their long diameter corresponds 
with the long axis of the bone, and their tubuli cross the direction of the 
lamellae, and constitute a very delicate network in the basis substance, 
by communicating with each other, and with the tubuli of neighbouring 
cells. The tubuli of the cells nearest the Haversian canals terminate 
upon the internal surface of those cavities. The size of the cells varies 
in extreme measurement from ^uu to suo °f an mcri m their l° n g diame- 
ter, an ordinary average being y^g o ; the breadth of the oval cells is 
about one-half or one-third their length, and their thickness one-half 
their breadth. They are situated between the lamellae, to which circum- 
stance they owe their compressed form. 

* The above cut, which I have introduced to supply the manifest deficiency of Mr. 
Wilson's representation, is from a section of a human femur, about its middle, and ex- 
hibits the erratic course of the Haversian canals, and their relations to each other, and 
at the same time the general laminated condition of a long bone. This laminated con- 
dition is well shown by polarized light, which causes the corpuscles to disappear, and 
the laminae to come out boldly. — G. 

-f-Miiller and Henle conceived that the bone cells and tubuli were the principal seat 
of the calcareous matter. Hence they have been named calcigerous cells and tubuli. 



46 DEVELOPMENT OF BONE. 

In the fresh state, bones are invested by a dense fibrous membrane, 
the periosteum, which covers every part of their surface, with the excep- 
tion of the articular extremities, the latter being coated by a thin layer 
of cartilage. The periosteum of the bones of the skull is termed 'peri- 
cranium ; and the analogous membrane of external cartilages, perichon- 
drium. Lining the interior of the medullary canal of long bones, the 
Haversian canals, the cells of the cancelli, and the cells of short, flat, 
and irregular bones, is the medullary membrane, which acts as an internal 
periosteum. It is through the medium of the vessels ramifying in these 
membranes that the changes required by nutrition occur in bones, and 
the secretion of medulla into their interior is effected. The medullary 
canal, Haversian canals, and cells of long bones, and the cells of other 
bones, are filled with a yellowish oily substance, the medulla, which is 
contained in a loose areolar tissue formed by the medullary membrane. 

Development of Bone. — To explain the development, of bone it is ne- 
cessary to inform the student, that all organized bodies, whether belong- 
ing to the vegetable or the animal kingdom, are developed primordially 
from minute vesicles. These vesicles, or, as they are commonly termed, 
cells, are composed of a thin membrane containing a fluid or granular 
matter, and a small rounded mass, the nucleus, around which the cell was 
originally formed. Moreover, the nucleus generally contains one or 
more small round granules, the nucleolus or nucleoli. From cells having 
this structure all the tissues of the body are elaborated ; the ovum itself 
originally presented this simple form, and the embryo at an early period 
is wholly composed of such nucleated cells. In their relation to each 
other, cells may be isolated and independent, as is exemplified in the 
corpuscles of the blood, chyle, and lymph ; secondly, they may cohere 
by their surfaces and borders, as in the epiderma and epithelium; thirdly, 
they may be connected by an intermediate substance, which is then 
termed intercellular, as in cartilage and bone ; and fourthly, they may 
unite with each other in rows, and upon the removal, by liquefaction, of 
the adherent surfaces, be converted into hollow tubuli. In the latter mode 
capillary vessels are formed, as also are the tubuli of nerve and muscular 
fibre. One of the properties of cells may also be adverted to in this place ; 
it is that of reproducing similar cells in their interior. In this case the 
nucleoli become the nuclei of the secondary cells, and as the latter increase 
in size, the membrane of the primary or parent cell is lost. 

Bone, in its earliest stage, is composed of an assemblage of these mi- 
nute cells, which are soft and transparent, and are disposed within the 
embryo in the site of the future skeleton. From the resemblance which 
the soft tissue bears to jelly, this has been termed the gelatinous stageii 
osteo-genesis. As development advances, the cells, heretofore loosew 
collected together, become separated by the interposition of a transparent 
intercellular substance, which is at first fluid, but gradually becomes hard 
and condensed. The cartilaginous stage of osteo-genesis is now esta- 
blished, and cartilage is shown to consist of a transparent matrix, having 
minute cells disseminated at pretty equal distances, and without order 
through its structure. Coincident with the formation of cartilage is the 
development of vascular canals in its substance, the canals beino- formed 
by the union of the cells in rows, and the subsequent liquefaction of the 
adhering surfaces. The change which next ensues in the concentration 
of the vascular canals towards some (5ne point ; 'for example, the centre 



DEVELOPMENT OF BONE. 



47 



of the shaft in a long, or the mid-point of a flat bone, and here the punctum 
ossifications, or centre of ossification, is established. What determines 
the vascular concentration now alluded to, is a question not easily solved, 
but that it takes place is certain, and the vascular punctum is the most 
easily demonstrable of all the phenomena of ossification. 



During the formation of 



Fig. 13.* 



A 

•0 <&« 



@ 



*0 •*> 
4*V 



Q> Sit, 



<S>^> 






> 3> 

a 



§>°® «aton© 



:f 






$ 



r «< 



& N<$> 



80 



& 



the punctum ossificationis, 
changes begin to be appa- 
rent in the cartilage cells. 
Originally they are simple 
nucleated cells (sn'oo t0 
2050 °f an mcn m diame- 
ter), having a rounded 
form. As growth pro- 
ceeds, they become elon- 
gated in their figure, and 
it is then perceived that 
each cell contains two and often three nucleoli, around which smaller cells 
are in progress of formation. 

If we examine them nearer g ' 14 t 

to the punctum ossificationis, 
we find that the young or 
secondary cells have each 
attained the size of the pa- 



rent cell (20V0 °f an inch), 
the membrane of the parent 
cell has disappeared, and 
the young cells are separated 
to a short distance by freshly 
effused intercellular substance, 
a more remarkable 
change has ensued, 
the energy of cellule 
reproduction has 
augmented with 
proximity to the os- 
sifying point, and 
each cell in place of 
producing two, gives 
birth to four, five, or 
six young cells, 
which rapidly de- 




Nearer still to the punctum ossificationis 

Fig. 15.* 







* Figures illustrative of the development of bone; they are magnified 155 times, 
and drawn with the camera lucida. a. A portion of cartilage the farthest removed from 

the seat of ossification, showing simple nucleated cells, having an ordinary size of — _' 

of an inch, long diameter, b. The same cartilage, nearer the seat of ossification ; each 
simple cell has produced two, which are a little larger than the cells in figure a. 

f Ihe same cartilage, still nearer the seat of ossification; each single cell of b has 
given birth to four, five, or six cells, which form clusters. These clusters become 
larger towards the right of the figure, and their cells more numerous and larger, _ » 
of an inch, long diameter. 

I The same cartilage at the seat of ossification ; the clusters of cells are arranged in 
columns; the intercellular spaces between the columns being 1 of an inch in 



48 DEVELOPMENT OF BONE. 

stroy the parent membrane and attain a greater size ( T5 Vo °f an mcn ) than 
the parent cell, each cell being, as in the previous case, separated to a 
slight extent from its neighbour by intercellular substance. By one other 
repetition -of the same process, each cell producing four, or five, or six 
young cells, a cluster is formed, containing from thirty to fifty cells. These 
clusters lie in immediate relation with the punctum ossificationis ; they are 
oval in figure (about ^o m l en g tn by - 5 £ n in breadth), and placed in the 
direction of the longitudinal axis of the bone. The cells composing the 
cluster lie transversely with regard to its axis. In the first instance they 
are closely compressed, but by degrees are parted by a thin layer of inter- 
cellular substance, and each cluster is separated from neighbouring clus- 
ters by a broader layer (3 ^50 °f an inch) of intercellular substance. Such 
are the changes which occur in cartilage preparatory to the formation of 
bone. 

Ossification is accomplished by the formation of very fine and delicate 
fibres within the intercellular substance : this process commences at the 
punctum ossificationis, and extends from that point through every part of 
the bone, in a longitudinal direction in long, and in a radiated manner in 
flat bones. Starting from the punctum ossificationis, the fibres embrace 
each cluster of cells, and then send branches between the individual cells 
of each group. In this manner the network, characteristic of bone, is 
formed, while the cells by their conjunction constitute the permanent 
areolae and Haversian canals. With a high magnifying power, the deli- 
cate ossific fibres here alluded to are seen themselves to be composed of 
minute cells having an elliptical form and central nuclei. These cells 
attract into their interior the calcareous salts of the blood, and their nuclei 
become developed, as I believe, into the future corpuscles of Purkinje. 
It is possible also that some of the cartilage cells become corpuscles of 
Purkinje in the fully developed bone. 

During the progress of the phenomena above described, the contents 
of the cells undergo certain changes. At first, their contents are transpa- 
rent, then they become granular, and still later opaque, from the presence 
of amorphous matter mingled with nuclei, nucleoli, and the remains of 
secondary cells. In the latter state they also contain an abundance of 
minute oil-globules. These latter increase in size as the ossific changes 
advance, and in the newly formed osseous areolae they are very numerous 
and have attained the ordinary size of adipose cells. 

Cartilaginification is complete in the human embryo at about the sixth 
week ; and the first point of ossification is observed in the clavicle at 
about the seventh week. Ossification commences at the centre, and 
thence proceeds towards the surface ; in flat bones the osseous tissue ra- 
diates between two membranes from a central point towards the periphery, 
in short bones from a centre towards the circumference, and in long bones 
from a central portion, diophysis, towards a secondary centre, epiphysis, 
situated at each extremity. Large processes, as the trochanters, are pro- 
vided with a distinct centre of development, which is named apophysis. 

breadth. To the right of the figure osseous fibres are seen occupying the intercellular 
•paces, at first bounding the clusters laterally, then splitting them longitudinally and 
encircling each Beparate cell. The greater opacity of the right-hand border is due to a 
three old cause, the increase of osseous fibres, the opacity of the contents of the cells 
and the multiplication of oil-globules. In the lower part of the figure some attemni 
has been made to show the texture of the cell< ^ 



DEVELOPMENT OF BONE. 49 

The growth of bone in length takes place at the extremity of the dia- 
physis, and in bulk by fresh deposition on the surface ; while the medul- 
lary canal is formed and increased by absorption from within. 

The period of ossification is different in different bones ; the order of 
succession may be thus arranged : — 

During the fifth week, ossification commences in the clavicle, lower 
jaw, and upper jaw. 

During the sixth w T eek, in the femur, humerus, tibia, radius, and ulna. 

During the seventh and eighth weeks, in the fibula, frontal, occipital, 
sphenoid, ribs, parietal, temporal, nasal, vomer, palate, vertebrae, first 
three pieces of sacrum, malar, metacarpus, metatarsus, third phalanges of 
the hands and feet, and ilium. 

During the third month, in the first and second phalanges of the hands 
and feet, lachrymal bone, and ischium. 

During the fifth month, in the mastoid portion of the temporal, ethmoid, 
inferior turbinated, sternum, os pubis, and last two pieces of sacrum. 

During the sixth month, in the body and odontoid process of the axis, 
and in the calcaneus. 

During: the seventh month, in the astragalus. 

During the tenth month, in the cuboid bone and os hyoides. 

During the first year, in the" coracoid process of the scapula ; first piece 
of the coccyx, inferior turbinated bone, last piece of the sternum, anterior 
arch of the atlas, os magnum, os unciforme, and external cuneiform bone. 

During the third year, in the cuneiform of the carpus, internal cuneiform 
of the tarsus, and patella. 

During the fourth year, in the middle cuneiform and scaphoid of the 
tarsus. 

During the fifth year, in the trapezium and os semilunare. 

During the seventh year, in the second piece of the coccyx. 

During the eighth year, in the scaphoid of the carpus. 

During the ninth year, in the os trapezoides. 

During the twelfth year, in the os fisiforme and third piece of the coccyx. 

During the eighteenth year, in the fourth piece of the coccyx. 

The ossicula auditus are the only bones completely ossified at birth; the 
vertebrae are not completed until the five-and-twentieth year. 

The entire osseous framework of the body constitutes the skeleton, which 
in the adult man is composed of two hundred and forty-six distinct bones. 
They may be thus arranged : — 

Head 8 

Ossicula auditus 6 

Face 14 

Teeth 32 

Vertebral column, including sacrum and coccyx 26 

Os hyoides, sternum, and ribs 26 

Upper extremities 64 

Lower extremities 62 

Sesamoid bones 8 



246 



The skeleton is divisible into : 1 . The vertebral column, or central axis. 
2. The head and face, or superior development of the central axis. 3. 
5 D 



.">0 VERTEBRAL COLUMN. 

The hyoid arch. 4. The thoracic arch and upper extremities. 5. The 
pelvic arch and lower extremities. 

VERTEBRAL COLUMN. 

The vertebral column is the first and only rudiment of internal skeleton 
in the lower Vertebrata, and constitutes the type of that great division of 
the animal kingdom. It is also the first developed portion of the skeleton 
in man, and the centre around which all the other parts are produced. 
In its earliest formation it is a simple cartilaginous cylinder, surrounding 
and protecting the primitive trace of the nervous system ; but, as it advances 
in growth and organisation, it becomes divided into distinct pieces, which 
constitute vertebrae. 

The vertebrae are divided into true and false. The true vertebras are 
twenty-four in number, and are classified, according to the three regions 
of the trunk which they occupy, into cervical, dorsal, and lumbar. The 
false vertebras consist of nine pieces united into two bones, the sacrum and 
coccyx. The arrangement of the vertebrae may be better comprehended 
by means of the accompanying table : — 

C 7 Cervical, 

True vertebrae 24 < 12 Dorsal, 
( 5 Lumbar. 

False vertebrae 9 < . ^ ' 

I 4 Coccyx. 

Characters of a Vertebra. — A vertebra consists of a body, two laminae, 
a spinous process, two transverse processes, and four articular processes. 
The body is the solid part of the vertebra ; and, by its articulation with 
adjoining vertebrae, gives strength and support to the trunk. It is flattened 
above and below, convex in front, and slightly concave behind. Its an- 
terior surface is constricted around the middle, and pierced by a number 
of small openings which give passage to nutritious vessels. Upon its pos- 
terior surface is a single irregular opening, or several, for the exit of the 
venae basis vertebrae. 

The laminae commence upon the sides of the posterior part of the body 
of the vertebra by two pedicles; they then expand; and, arching back- 
wards, enclose a foramen which serves for the protection of the spinal 
cord. The upper and lower borders of the laminae are rough for the at- 
tachment of the ligamenta subflava. The concavities above and below the 
pedicles are the intervertebral notches. The spinous process stands back- 
wards from the angle of union of the laminae of the vertebra. It is the 
succession of these projecting processes along the middle line of the back, 
that has given rise to the common designation of the vertebral column, the 
spine. The use of the spinous process is for the attachment of muscles. 
The transverse processes project one at each side from the laminae of the 
vertebra ; they are intended for the attachment of the muscles. The arti- 
cular processes, four in number, stand upwards and downwards from the 
laminae of the vertebra, to articulate with the vertebra above and below. 

Cervical Vertebrae. — In a cervical vertebra the body is smaller than 
in the other regions ; it is thicker before than behind, broad from side 
to side, concave on the upper surface, and convex below ; so that, when 
articulated, the vertebra: lock the one into the other. The lamina are 



CERVICAL VERTEBRAE. 



51 



Fig. 16. 



narrow and long, and the included spinal fo- 
ramen large and triangular. The superior in- 
tervertebral notches are slightly deeper than the 
inferior ; the inferior being the broadest. The 
spinous process is short and bifid at the extre- 
mity, increasing in length from the fourth to the 
seventh. The transverse processes are also short 
and bifid, and deeply grooved along the upper 
surface for the cervical nerves. Piercing the 
base of the transverse process is the vertebral 
foramenf, which gives passage to the vertebral 
artery and vein, and vertebral plexus of nerves. The transverse processes 
in this region are formed by two small developments which proceed, the one 
from the side of the body, the other from the pedicle of the vertebra, and 
unite near their extremities to enclose the circular area of the vertebral 
foramen. The anterior of these developments is the rudiment of a cervi- 
cal rib ; and the posterior, the analogue of the transverse processes in the 
dorsal region. The extremities of these developments are the anterior 
and posterior tubercles of the. transverse process. The articular processes 
are oblique ; the superior looking upwards and backwards ; and the infe- 




rior, downwards and forwards. 

There are three peculiar vertebra? in the cervical region : — The first, or 
atlas ; the second, or axis ; and the seventh, or vertebra prominens. 

The Atlas (named from supporting the head) is a simple ring of bone, 
without body, and composed of arches and processes. The anterior arch 
has a tubercle on its anterior surface, for the attachment of thelongus colli 
muscle : and on its posterior aspect is a smooth surface, for the articulation 
of the odontoid process of the axis. 

The posterior arch is longer and more „. 

slender than the anterior, and flattened 
from above downwards ; at its middle is 
a rudimentary spinous process ; and upon 
its upper surface, near the articular pro- 
cesses, a shallow groove§ at each side, 
which represents a superior intervertebral 
notch, and supports the vertebral artery 
previously to its passage through the 
dura mater, and the first cervical nerve. 

* A central cervical vertebra, seen upon its upper surface. 1. The body, concave in 
the middle, and rising on each side into a sharp ridge. 2. The lamina. 3. The pedi- 
cle, rendered concave by the superior intervertebral notch. 4. The bifid spinous process. 
5. The bifid transverse process. The figure is placed in the concavity between the an- 
terior and posterior tubercles, between the two processes which correspond with the 
rudimentary rib and the true transverse process. 6. The vertebral foramen. 7. The 
superior articular process, looking backwards and upward*. 8. The inferior articular 
process. 

•j- Sometimes, as in a vertebra now before me, a small additional opening exists by 
the side of the vertebral foramen, in which case it is traversed by a second vein. 

\ The upper surface of the atlas. 1. The anterior tubercle projecting from the ante- 
rior arch. 2. The articular surface for the odontoid process upon the posterior surface 
of the anterior arch. 3. The posterior arch, with its rudimentary spinous process. 4. 
The intervertebral notch. 5. The transverse process.^ 6. The vertebral foramen. 7. 
Superior articular surface. 8. The tubercle for the attachment of the transverse liga- 
ment. The tubercle referred to is just above the head of the figure ; the convexity be- 
low it is the margin of the inferior articulating process. 

§ This groove is sometimes converted into a foramen. 




52 ATLAS AND AXIS VERTEBRA PROMINENS. 

The intervertebral notches are peculiar, from being situated behind the 
articular processes, instead of before them as in the other vertebras. The 
transverse processes are remarkably large and long, and pierced by the 
foramen for the vertebral artery. The articular processes are situated upon 
the most bulky and strongest part of the atlas. The superior are oval and 
concave, and look inwards, so as to form a kind of cup for the condyles 
of the occipital bone, and are adapted to the nodding movements of the 
head; the inferior are circular, and nearly horizontal, to permit of the ro- 
tatory movements. Upon the inner face of the lateral mass which sup- 
ports the articular processes, is a small tubercle at each side, to which the 
extremities of the transverse ligament are attached, a ligament which di- 
vides the ring of the atlas into two unequal segments •; the smaller for 
receiving the odontoid process of the axis, and the latter to give passage 
to the spinal cord and its membranes. 

The Axis (vertebra dentata) is so named from having a process upon 
which the head turns as on a pivot. The body is of large size, and sup- 
ports a strong process, the odontoid, which rises perpendicularly from its 
upper surface. The odontoid process presents two articulating surfaces ; 
one on its anterior face, to articulate with the anterior arch of the atlas; 
the other on its posterior face, for the transverse ligament; the latter sur- 
face constricts the base of the process, which has given rise to the term neck 
applied to this part. Upon each side of its apex is a rough depression, for 
the attachment of the alar ligaments ; and running down from its base or? 
p. lg * the anterior surface of the body of the vertebra 2 

vertical ridge, with a depression at each side.foi 
the attachment of the longus colli muscle. The 
lamince are large and strong, and unite posteriorly 
to form a long and bifid spinous process, which is 
concave beneath. The transverse processes are 
quite rudimentary, not bifid, and project only so 
far as to enclose the vertebral foramen, which is 
directed obliquely outwards instead of perpendicu- 
larly as in the other vertebrae. The superior articulating processes are 
situated upon the body of the vertebra on each side of the odontoid process. 
They are circular and nearly horizontal, having a slight inclination out- 
wards. The inferior articulating processes look downwards and forwards, 
as do the same processes in the other cervical vertebras. The superior in- 
tervertebral notch is remarkably shallow, and lies behind the articular pro- 
cess as in the atlas. -The lower surface of the body is convex, and is 
received into the concavity upon the upper surface of the third vertebra. 

The Vertebra prominens, or seventh cervical, approaches in character 
to the upper dorsal vertebrae. It has received its designation from having 
a very long spinous process, which is single and terminated by a tubercle, 
and forms a considerable projection on the back part of the neck ; to the 
extremity of this process the ligamentum nuchas is attached. The trans- 
verse processes are ftut slightly grooved along the upper surface, have 

* A lateral view of the axis. 1. The body; the figure is placed on the depression 
which gives attachment to the longus colli. 2. The odontoid process. 3. The smooth 
facet on the anterior surface of the odontoid process which articulates with the anterior 
arch of the atlas; the facet foj- the transverse ligament is beneath No. 2, where the 
constriction called the neck of the odontoid processes seen ; the bulk of the process be- 
tween 2, 3, would represent its head. 4. The lamina. 5. The spinous process. 6. 
The transverse process, pierced obliquely by the vertebral foramen. 7 The superior 
arucular surface. 8. The inferior articular process. 




DORSAL VERTEBRAE — LUMBAR VERTEBRA. 



53 



Fig. 19. 




each a small foramen for the transmission of the vertebral vein, and pre- 
sent only a rudimentary bifurcation at their extremity. Sometimes the 
anterior tubercle represents a small but distinct rib. 

Dorsal Vertebra. — The body of a dorsal vertebra is as long from before 
backwards as from side to side, particularly in the middle of the dorsal 
region ; it is thicker behind than before, and marked on each side by two 
half-articulating surfaces for the heads of two ribs. The pedicles are strong, 
and the lawince broad and thick ; the spinal foramen small and round, 
and the inferior intervertebral notch of large 
size, the superior can scarcely be said to exist. 
The spinous process is long, prismoid, directed 
very obliquely downwards, and terminated by 
a tubercle. The transverse processes are large 
and strong, and directed obliquely back- 
wards. Upon the anterior and superior as- 
pect of their summits is a small facet for the 
articulation of the tubercle of a rib. The ar- 
ticular processes are vertical, the superior facing 
directly backwards, and the inferior directly 
forwards. 

The peculiar vertebrae in the dorsal region are the first, ninth, tenth, 
eleventh, and twelfth. The first dorsal vertebra approaches very closely 
in character to the last cervical. The body is broad from side to side, 
and concave above. The superior articular processes are oblique, and 
the spinous process horizontal. It has an entire articular surface for the 
first rib, and a half surface for the second. The ninth dorsal vertebra has 
only one half articular surface at each side. The tenth has a single entire 
articular surface at each side. The eleventh and twelfth have each a single 
entire articular surface at each side ; they approach in character to the 
lumbar vertebras ; their transverse processes are very short, trifid at their 
summits, and have no articulation with the corresponding ribs. The 
transverse processes of the twelfth dorsal vertebra are quite rudimentary, 
and its inferior articular processes look outwards. 

Lumbar Vertebrae. — These are the largest 
pieces of the vertebral column. The body 
is broad and large, and thicker before than 
behind. The pedicles very strong; the la- 
mince short, thick, and broad ; the inferior 
intervertebral notches very large, and the 
spinal foramen large and oval. The spin- 
ous process is thick and broad. The trans- 
verse processes (costiform processes) are 
slender, pointed, and directed only slightly 



Fig. 20.f 




* A lateral view of a dorsal vertebra. 1. The body. 2, 2. Articular facets for the 
heads of ribs. 3. The pedicle. 4. The superior intervertebral notch. 5. The inferior 
intervertebral notch. 6. The spinous process. 7. The extremity of the transverse pro- 
cess, marked by an articular surface for the tubercle of a rib. 8. The two superior 
articular processes looking backwards. 9. The two inferior articular processes looking 
forwards. 

f A lateral view of a lumbar vertebra. 1. The body. 2. The pedicle. 3. The su- 
perior intervertebral notch. 4. The inferior intervertebral notch. 5. The spinous pro- 
cess. 6. The transverse process. 7. The superior articular processes. 8. The inferior 
articular processes. 9. The posterior transverse process. 



51 LUMBAR VERTEBRAE. 

backwards. The superior articular processes are concave, and look back- 
wards and inwards ; the inferior convex, and look forwards and outwards. 
Projecting backwards and upwards from the superior articular process is 
a short and flattened tubercle or posterior transverse process, and in a 
strongly marked vertebra there is not unfrequently at the base of this a 
smaller tubercle which has a direction downwards. The last lumbar ver- 
tebra differs from the rest in having the body very much bevelled poste- 
riorly, so as to be thick in front and thin behind, and the transverse pro- 
cess thick and large. 

General Considerations. — Viewed as a whole, the vertebral column 
represents two pyramids applied base to base, the superior being formed 
by all the vertebrae from the second cervical to the last lumbar, and the . 
inferior by the sacrum and coccyx. Examined more attentively, it will 
be seen to be composed of four irregular pyramids, applied to each other 
by their smaller extremities and by their bases. The smaller extremity 
of the uppermost pyramid is formed by the axis, or second cervical ver- 
tebra; and its base, by the first dorsal. The second pyramid is inverted; 
having its base at the first dorsal, and the smaller end at the fourth, i The 
third pyramid commences at the fourth dorsal, and gradually enlarges to 
the fifth lumbar. The fourth pyramid is formed by the sacrum and 
coccyx. 

The bodies of the vertebrae are broad in the cervical region ; narrowed 
almost to an angle in the middle of the dorsal, and again broad in the 
lumbar region. The arches are broad and imbricated in the cervical and 
dorsal regions, the inferior border of each overlapping the superior of the 
next ; in the lumbar region an interval is left between them. A consider- 
able interval exists between the cranium and atlas, and another between 
the last lumbar vertebra and sacrum. 

The spinous processes are horizontal in the cervical, and become gradu- 
ally oblique in the upper part of the dorsal region. In the middle of the 
dorsal region they are nearly vertical and imbricated, and towards its 
lower part assume the direction of the lumbar spines, which are quite 
horizontal. The transverse processes developed in their most rudimentary 
form in the axis, gradually increase in length to the first dorsal vertebra. 
In the dorsal region they project obliquely backwards, and diminish sud- 
denly in length in the eleventh and twelfth vertebrae where they are very 
small. In the lumbar region they increase to the middle transverse pro- 
cess, and again subside in length to the last. 

The transverse processes consist essentially of two parts, the anterior 
of which in the dorsal region is the rib, while the posterior retains the 
name of the transverse process. In the cervical region these two elements 
are quite apparent, both by their different points of attachment to the ver- 
tebra, and by the vertebral foramen which divides them at their base. In 
the lumbar region the so-called transverse processes are in reality lumbar 
ribs, while the transverse processes will be found behind them in a rudi- 
mentary state, developed, like the true transverse procespfe in the cervical 
region, from the superior articular processes. When the anterior and 
posterior transverse processes are examined in relation with each other, 
they will be observed to converge ; if they were prolonged they would 
unite as in the cervical region and enclose a foramen, or they would rest 
in contact as in the dorsal region, or become consolidated as in the form- 
ation of the sacrum. Moreover, the posterior transverse processes nre 



DEVELOPMENT OF VERTEBRAE. 55 

directed upwards, and if they were prolonged, they would come into con- 
tact with a small tubercle which is found at the base of the posterior trans- 
verse process (in strongly -marked vertebrae) in the vertebra above. This 
junction would form a posterior intervertebral foramen, as actually occurs 
in the sacrum. In brief, the lumbar vertebrae .exhibit those transitional 
changes which are calculated, by an easy gradation, to convert separate 
vertebrae into a solid bone. The transverse processes of the eleventh and 
twelfth dorsal vertebrae are very interesting in a transcendental point of 
view, as exhibiting a tendency which exists obscurely in all the rest, 
namely, to trifurcate. Now, supposing these three branches to be length- 
ened in order to fulfil their purposes, the anterior would constitute the 
articulation or union with a rib, while the superior and inferior would join 
similar branches in the vertebra above and below, and so form the poste- 
rior intervertebral foramen. 

The intervertebral foramina formed by the juxtaposition of the notches 
are smallest in the cervical region, and gradually increase to the last lum- 
bar. On either side of the spinous processes, and extending the whole 
length of the column, is the vertebral groove, which is shallow and broad 
in the cervical, and deeper and narrower in the dorsal and lumbar regions. 
It lodges the principal muscles of the back. 

Viewed from the side, the vertebral column presents several curves, the 
principal of which is situated in the dorsal region, the concavity looking 
forwards. In the cervical and lumbar regions the column is convex in 
front ; and in the pelvis an anterior concave curve is formed by the sacrum 
and coccyx. Besides the antero-posterior curves, a slight lateral curve 
exists in the dorsal region, having its convexity towards the right side. 

Development. — The vertebras are developed by three primary and five 
secondary centres or epiphyses. The primary centres are, one for each 
lamella, and one for the body; the epiphyses, one for the apex of the 
spinous process, one for that of each transverse process, and one for the 
upper and.under surface of the body. Exceptions to this mode of deve- 
lopment are met with in the atlas, axis, vertebra prominens, and lumbar 
vertebrae. The atlas has four centres : one for each lateral mass, one 
(sometimes two) for the anterior arch, and one for the centre of the poste- 
rior arch. The axis has five : one (sometimes two) for the body, two for 
the odontoid process, appearing side by side in its base, and one for each 
lamella. The vertebra prominens has two additional centres for the ante- 
rior or costal segments of the transverse processes, and the lumbar vertebra 
two for the posterior segments of the transverse processes. 

The primary centres of the vertebrae make their appearance during the 
seventh or eighth week of embryonic existence, the lamella being some- 
what in advance of that for the body. From the former are produced the 
spinous, transverse, and articular processes, and the sides of the body ; 
they unite, to complete the arch, one year after birth, and with the body 
during the fifth year. The epiphyses, for the extremities of the spinous 
and transverse processes, make their appearance at fifteen or sixteen, and 
become united between twenty and twenty-five. The epiphyses of the 
body are somewhat later in appearance, and are consolidated between the 
periods of twenty-five and thirty years of age. 

The ossific centres for the lateral masses of the atlas appear at the same 
time with those of the other vertebrae ; they unite posteriorly at the end 
of the second year, by the intervention of the centre for the posterior arch. 



56 SACRUM. 

The one or two centres of the anterior arch appear during the first year, 
and become consolidated with the lateral pieces during the fifth or sixth 
year. The axis develops its lateral pieces at the' same time with the rest 
of the vertebrae ; they join posteriorly soon after birth, and with the body 
during the fourth or fifth year. The centres for the body and odontoid 
process appear during the sixth month, and are consolidated during the 
third year. The body of the axis is more largely developed at birth than 
that of the other vertebras. The costal segments of the vertebra prominens 
appear during the second month, and become united to the body at the 
fifth or sixth year. These processes sometimes remain permanently sepa- 
rate, and constitute a cervical rib. The transverse process of the first 
lumbar vertebra has sometimes a distinct centre, which may remain per- 
manently separate, in that case forming a lumbar rib. 

The ossification of the arches of the vertebrae commences from above, 
and proceeds gradually downwards ; hence arrest of development gives 
rise to spina bifida, generally in the loins. Ossification of the bodies, on 
the contrary, commences from the centre, and proceeds from that point 
towards the extremities of the column ; hence imperfection of the bodies 
occurs either in the upper or lower vertebrae. 

Attachment of Muscles. — To the atlas are attached ten pairs of muscles; 
the longus colli, rectus anticus minor, rectus lateralis, rectus posticus 
minor, obliquus superior and inferior, splenius colli, levator anguli scapulas, 
first interspinals, and first intertransversales. 

To the axis are attached twelve pairs, viz. : the longus colli, intertrans- 
versales, obliquus inferior, rectus posticus major, supraspinalis, interspi- 
nales, semi-spinalis colli, multifidus spinas, levator anguli scapula?, splenius 
colli, transversalis colli, and scalenus posticus. 

To the remaining vertebrae collectively, thirty-three pairs ; — viz. poste- 
riorly, the trapezius, latissimus dorsi, levator anguli scapulas, rhomboideus 
minor and major, serratus posticus superior and inferior, splenius, sacro- 
lumbalis, longissimus dorsi, spinalis dorsi, cervicalis ascendens, trans- 
versalis colli, trachelo-mastoideus, complexus, semi-spinalis dorsi and 
colli, multifidus spinas, supraspinalis, interspinales, intertransversales, 
levatores costarum : anteriorly, the rectus anticus major, longus colli, 
scalenus anticus and posticus, psoas magnus, psoas parvus, quadratus 
lumborum, diaphragm, obliquus internus and transversalis. 

The Sacrum is a triangular bone, situated at the lower extremity of the 
vertebra] column, and formed by the consolidation of five false vertebras. 
It is divisible into an anterior and posterior surface, two lateral and a 
superior border, and an inferior extremity. 

The anterior surface is concave, and marked by four transverse lines, 
which indicate its original constitution of five separate pieces. At the 
extremities of these lines, on each side, are the four anterior sacral fora- 
mina, which diminish in size from above downwards, and transmit the 
anterior sacral nerves. The projection of the superior piece is the sacro- 
vertebral angle or promontory. 

The posterior surface is narrower than the anterior and convex. Upon 
the middle line is a rough crest formed by the rudiments of four spinous 
processes, the fifth remaining undeveloped and exposing the lower termi- 
nation of the sacral canal. Immediately external to and parallel with the 
median crest, is a range of five small tubercles which represent the poste- 




SACRUM. 57 

rior transverse processes of the true vertebrae ; beyond these is a shallow 
groove in which the four posterior sacral foramina open, and farther out- 
wards, a range of five tubercles corresponding with the anterior or costal 
transverse processes of the lumbar vertebrae. The lowest pair of the pos- 
terior transverse tubercles bound on each side the termination of the sacral 
canal, and send each a process downwards to articulate with the coccyx. 
The two descending processes are the sacral cornua. The posterior sacral 
foramina are smaller than the anterior, and transmit the posterior sacral 
nerves. Of the anterior transverse tubercles the first corresponds with the 
angle of the superior border of the bone ; the second is small, and enters 
into the formation of the sacro-iliac articulation ; the third is large, and 
gives attachment to the oblique sacro-iliac ligament,; the fourth and fifth 
are smaller, and serve for the attachment of the j^g. 21.* 

sacro-ischiatic ligaments. The lateral border 
of the sacrum presents superiorly a broad and 
ear-shaped (auricular) surface to articulate with 
the ilium ; and inferiorly a sharp edge, to which 
the greater and lesser sacro-ischiatic ligaments 
are attached. On the superior border, in the 
middle line, is an oval articular surface, which 
corresponds with the under part of the body of 
the last lumbar vertebra ; and on each side a 
broad triangular surface, which supports the 
lumbo-sacral nerve and psoas magnus muscle. 
Immediately behind the vertebral articular sur- 
face is the triangular entrance of the sacral canal ; and on each side of this 
opening an articular process, which looks backwards and inwards, like the 
superior articular processes of the lumbar vertebrae. In front of each 
articular process is an intervertebral notch. The inferior extremity of the 
bone presents a small .oval surface which articulates with the coccyx ; and 
on each side a notch, which, with a corresponding notch in the upper 
border of the coccyx, forms the foramen for the transmission of the fifth 
sacral nerve. 

The sacrum presents some variety in respect of curvature, and of the 
number of pieces which enter into its structure. The curve is often very 
slight, and is situated only near the lower part of the bone ; while in other 
subjects it is considerable, and occurs at the middle of the sacrum. The 
sexual differences in the sacrum relate to its greater breadth, and the 
greater angle which it forms with the rest of the vertebral column in the 
female, rather than to any peculiarity in shape. It is sometimes composed 
of six pieces, more rarely of four, and, occasionally, the first and second 
pieces remain permanently separate. 

Development. — By twenty-one points of ossification ; five for each of the 
three first pieces, viz. one for the body, one for each lateral portion, and 
one for each lamina ; and three for each of the two last, namely, one for 

* The sacrum seen upon its anterior surface. 1, 1. The transverse lines marking the 
original constitution of the bone of four pieces. 2, 2. The anterior sacral foramina. 
3. The promontory of the sacrum. 4. The ear-shaped surface which articulates with 
the ilium. 5. The sharp edge to which the sacro-ischiatic ligaments are attached 
6. The vertebral articular surface. 7. The broad triangular surface which supports the 
psoas muscle and lumbo-sacral nerve. 8. The articular process of the right side. 
. 9. The inferior extremity, or apex of the sacrum. 10. One of the sacral cornua. 
11. The notch which is converted into a foramen by the coccyx. 



58 coccyx. 

the body, and one for each lateral portion. In the progress of growth, 
and after puberty, fourteen epiphysal centres are added, namely, two for 
the surfaces of each body, one for each auricular surface, and one for the 
thin edge of each lateral border. Ossification begins in the bodies of the 
sacral pieces somewhat later than in those of the true vertebrae ; the first 
three appearing during the eighth and ninth week, and the last two at about 
the middle of the intra-uterine existence. Ossification of the lamellse 
takes place during the interval between the sixth and the ninth month. 
The epiphyses for the upper and under surface of the bodies are developed 
during the interval between the fifteenth and eighteenth year; and for the 
auricular and marginal piece, after twenty. The two lower vertebral 
pieces, although the last to appear, are the first to be completed (between 
the fourth and fifth year), and to unite by their bodies. The union of the 
bodies takes place from below upwards, and finishes between the twenty- 
fifth and the thirtieth year, with the first two pieces. 

Articulations. — With four bones ; the last lumbar vertebra, ossa inno- 
minata, and coccyx. 

Attachment of Muscles. — To seven pairs ; in front the pyriformis, on 
the side the coccygeus, and behind the gluteus maximus, latissimus dorsi, 
longissimus dorsi, sacro-lumbalis, and multifidus spinse. 

The Coccyx (xoxxug cuckoo, from resembling a cuckoo's beak) is com- 
posed of four small pieces, which form the caudal termination of the ver- 
tebral column. The superior piece is broad, and expands laterally into 
two transverse processes ; it is surmounted by an oval articular surface 
and two cornua, the former to articulate with the apex of the sacrum, and 
the latter with the sacral cornua. The lateral wings sometimes become 
connected with the sacrum, and convert the notches for the fifth pair of 
sacral nerves into foramina. The remaining three pieces diminish in size 
from above downwards. 

Development. — By four centres; one for each piece. Ossification com- 
mences in the first piece soon after birth ; in the second, between five and 
ten years ; in the third, between ten and fifteen ; and in the fourth, be- 
tween fifteen and twenty. The pieces unite at an earlier period than the 
bodies of the sacrum, the first two pieces first, then the third and fourth, 
and lastly, the second and third. Between forty and sixty years, the 
coccyx becomes consolidated with the sacrum ; this event taking place 
later in the female than in the male. 

Articulations. — With the sacrum. 

Attachment of Muscles. — To three pairs, and one single muscle; gluteus 
maximus, coccygeus, posterior fibres of the levator ani, and sphincter ani. 

OF THE SKULL. 

The skull, or superior expansion of the vertebral column, is divisible 
into two parts, — the cranium and the face ; the former being adapted, by 
its form, structure, and strength, to contain and protect the brain, and the 
latter the chief organs of sense. 

The Cranium is composed of eight separate bones ; viz., the 
Occipital, Two temporal, 

Two parietal, Sphenoid, 

Frontal, Ethmoid. 



OCCIPITAL BONE. 



59 



Fig. 22* 




Occipital Bone. — This bone is situated at the posterior part and base 
of the cranium. It is trapezoid in figure, and divisible into two surfaces, 
four borders, and four angles. 

External Surface. — Crossing the middle of the bone transversely, from 
one lateral angle to the other, is a prominent ridge, the superior curved 
line. In the middle of the ridge is a 
projection, called the external occipital 
protuberance ; and descending from it a 
small vertical ridge, the spine. Above 
and below the superior curved line the 
surface is rough, for the attachment of 
muscles. About three-quarters of an 
inch below this line is another trans- 
verse ridge, the inferior curved line, 
and beneath the latter the foramen mag- 
num. On each side of the foramen 
magnum, nearer to its anterior than 
its posterior segment, and encroaching 
somewhat upon the opening, is an ob- 
long articular surface, the condyle, for 
articulation with the atlas. The con- 
dyles approach towards each other an- 
teriorly, and their articular surfaces look downwards and outwards. 
Directly behind each condyle is an irregular fossa, and a small opening, 
the posterior condyloid foramen, for the transmission of a vein to the lateral 
sinus. In front of the condyle is the anterior condyloid foramen, for the 
hypoglossal nerve ; and on the outer side of each condyle a projecting 
ridge, the transverse process, excavated in front by a notch which forms 
part of the jugular foramen. In front of the foramen magnum is a thick 
square mass, the basilar process, and in the centre of the basilar process a 
small tubercle for the attachment of the superior and middle constrictor 
muscles of the pharynx. 

Internal Surface. — Upon the internal surface is a crucial ridge, which 
divides the bone into four fossae ; the two superior or cerebral fossae lodging 
the posterior lobes of the cerebrum ; and the two inferior or cerebellar, 
the lateral lobes of the cerebellum. The superior arm of the crucial ridge 
is grooved for the superior longitudinal sinus, and gives attachment to the 
falx cerebri ; the inferior arm is sharp and prominent, for the attachment 
of the falx cerebelli, and slightly grooved for the two occipital sinuses. 
The transverse ridge gives attachment to the tentorium cerebelli, and is 
deeply grooved for the lateral sinuses. At the point of meeting of the 
four arms is a projection, the internal occipital protuberance, which corre- 
sponds with the similar process situated upon the external surface of the 
bone. The convergence of the four grooves forms a slightly depressed 
fossa, upon which rests the torcular Herophili. In the centre of the 

* The external surface of the occipital bone. 1. The superior curved line. 2. The 
external occipital protuberance. 3. The spine. 4. The inferior curved line. 5. The 
foramen magnum. 6. The condyle of the right side. 7. The posterior condyloid fossa, 
in which the posterior condyloid foramen is found. 8. The anterior condyloid foramen, 
concealed by the margin of the condyle. 9. The transverse process ; this process upon 
the internal surface of the bone forms the jugular eminence. 10. The notch in front of 
the jugular eminence which forms part of the jugular foramen. 1 1. The basilar process. 
12, 12. The rough projections into which the odontoid ligaments are inserted. 



60 



OCCIPITAL BONE. 



23. 




basilar portion of the bone is the foramen magnum, oblong in form, and 
larger behind than before, transmitting the spinal cord, spinal accessory 

nerves, and vertebral arteries. Upon 
the lateral margins of the foramen 
magnum are two rough eminences, 
which give attachment to the odon- 
toid ligaments, and immediately above 
these the openings of the anterior con- 
dyloid foramina. In front of the fora- 
men magnum is the basilar process, 
grooved on its surface, for supporting 
the medulla oblongata, and along each 
lateral border, for the inferior petrosal 
sinuses. On each side of the foramen 
magnum is a groove, for the termina- 
tion of the lateral sinus ; a smooth sur- 
face, which forms part of the jugular 
fossa; and a projecting process, which 
divides the two, and is called the 
jugular eminence. Into the jugular 
fossa will be seen opening the posterior condyloid foramen. 

The superior borders are very much serrated, and assist in forming the 
lambdoidal suture ; the inferior are rough, but not serrated, and articulate 
with the mastoid portion of the temporal bone by means of the addita- 
mentum suturae lambdoidalis. The jugular eminence and the side of the 
basilar process articulate with the petrous portion of the temporal bone, 
and the intermediate space, which is irregularly notched, forms the poste- 
rior boundary of the jugular foramen, or foramen lacerum posterius. 

The angles of the occipital bone are the superior, inferior, and two 
lateral. The superior angle is received into the interval formed by the 
union of the posterior and superior angles of the parietal bones, and cor- 
responds with that portion of the foetal head which is called the posterior 
fontanelle. The inferior angle is the articular extremity of the basilar 
process. The lateral angles at each side project into that interval formed 
by the articulation of the posterior and inferior angle of the parietal with 
the mastoid portion of the temporal bone. 

Development. — By seven centres ; four for the four parts of the expanded 
portion divided by the crucial ridge, one for each condyle, and one for 
the basilar process. Ossification commences in the expanded portion of 
the bone at a period anterior to the vertebrae ; at birth the four remaining 
pieces are distinct ; they are united at about the fifth or sixth year. After 
twenty the basilar process unites with the body of the sphenoid. 

* The internal surface of the occipital bone. 1. The left cerebral fossa. 2. The left 
cerebellar fossa. 3. The groove for the posterior part of the superior longitudinal sinus. 
4. The spine for the falx cerebelli, and groove for the occipital sinuses. 5. The groove 
for the left lateral sinus. 6. The internal occipital protuberance, the groove on which 
lodges the torcular Herophili. 7. The foramen magnum. 8. The basilar process, 
grooved for the medulla oblongata. 9. The termination of the groove for the lateral 
hiihs. bounded externally by the jugular eminence. 10. The jugular fossa; this fossa 
is <r,inpleted by the petrous portion of the temporal bone. 11. The superior border. 
1-'. The inferior border. 13. The border which articulates with the petrous portion of 
Tin- temporal bone, and which is grooved by the inferior petrosal sinus. 14. The ante- 
rior condyloid foramen. 



PARIETAL BONE. 



61 



Articulations. — With six bones; two parietal, two temporal, sphenoid, 
and atlas. 

Attachment of Muscles. — To thirteen pairs: to the rough surface above 
the superior curved line, the occipito-frontalis ; to the superior curved 
line, the trapezius and sterno-mastoid ; to the rough space between the 
curved lines, complexus, and splenius capitis ; to the space between the 
inferior curved line and the foramen magnum, the rectus posticus major 
and minor, and obliquus superior ; to the transverse process, the rectus 
lateralis ; and to the basilar process, the rectus anticus major and minor, 
and superior and middle constrictor muscles. 



Fig. 24* 




Parietal Bone. — The parietal 
bone is situated at the side and ver- 
tex of the skull ; it is quadrilateral in 
form, and divisible into an external 
and internal surface, four borders and 
four angles. The superior border is 
straight, to articulate with its fellow 
of the opposite side. The inferior 
border is arched and thin, to articu- 
late with the temporal bone. The 
anterior border is concave, and the 
posterior somewhat convex. 

External surface. — Crossing the 
bone in a longitudinal direction from 
the anterior to the posterior border, is an arched line, the temporal ridge, 
to which the temporal fascia is attached. In the middle of this line, and 
nearly in the centre of the bone, is the projection called the parietal emi- 
nence, which marks the centre of ossification. Above the temporal ridge 
the surface is rough, and covered by the aponeurosis of the occipito-fron- 
talis ; below the ridge the bone is smooth (planum semicircular e\ for the 
attachment of the fleshy fibres of the temporal muscle. Near the superior 
border of the bone, and at about one-third from its posterior extremity, 
is the parietal foramen, which transmits a vein to the superior longitudinal 
sinus. This foramen is often absent. 

Internal surface. — The internal table is smooth ; it is marked by nu- 
merous furrows, which lodge the ramifications of the arteria meningea 
media, and by digital fossoe which correspond with the convolutions of 
the brain. Along the upper border is part of a shallow groove, completed 
by the opposite parietal bone, which serves to contain the superior longitu- 
dinal Sinus. Some slight pits are also observable near this groove, which 
lodge the glandulae Pacchioni. 

, The anterior inferior angle is thin and lengthened, and articulates with 
the greater wing of the sphenoid bone. Upon its inner surface it is 
deeply channelled by a groove for the trunk of the arteria meningea 
media. This groove is frequently converted into a canal. The posterior 

* The external surface of the left parietal bone. 1. The superior or sagittal border. 
2. The inferior or squamous border. 3. The anterior or coronal border. 4. The poste- 
rior or lambdoidal border. 5. The temporal ridge; the figure is situated immediately 
in front of the parietal eminence. 6. The parietal foramen, unusually large in the bone 
from which this figure was drawn. 7. The anterior inferior angle. 8. The posterior 
inferior angle. 



62 



FRONTAL BONE. 




inferior angle is thick, and presents 
a broad and shallow groove for the 
lateral sinus. 

Development. — By a single centre. 
Ossification commences at the parie- 
tal eminence at the same time with 
the bodies of the vertebrae. 

Articulations. — With Jive bones ; 
with the opposite parietal bone, the 
occipital, frontal, temporal, and sphe- 
noid. 

Attachment of Muscles. — To one 
only,— the temporal. The occipito- 
frontalis glides over its upper sur- 
face. 



Frontal Bone. — The frontal bone bears some resemblance in form to 
the under valve of a scallop shell. It is situated at the anterior part of the 
cranium, forming the forehead, and assists in the construction of the roof 
of the orbits and nose. Hence it is divisible into a superior or frontal 
portion, and an inferior or orbito-nasal portion. Each of these portions 
presents for examination an external and internal surface, borders, and 
processes. 

External surface. — At about the middle of each lateral half of the fron- 
tal portion is a projection, the frontal eminence. Below these points are 
the superciliary ridges , large towards their inner termination, and becoming 
gradually smaller as they arch outwards : they support the eyebrows. 
Beneath the superciliary ridges are the sharp and prominent arches which 
form the upper margin of the orbits, the supra-orbital ridges. Externally 
the supra-orbital ridge terminates in the external angular process, and 
internally in the internal angular process ; at the inner third of this ridge 
is a notch, sometimes converted into a foramen, the supra-orbital notch, 
which gives passage to the supra-orbital artery, veins, and nerve. Be- 
tween the two superciliary ridges is a rough projection, the nasal tuberosi- 
ty ; this portion of the bone denotes by its prominence the situation of the 
frontal sinuses. Extending upwards and backwards from the external 
angular process is a sharp ridge, the commencement of the temporal ridge, 
and beneath this a depressed surface that forms part of the temporal fossa. 

The orbito-nasal portion of the bone consists of two thin processes, the 
orbital plates, which form the roof of the orbits, and of an intervening 
notch which lodges the ethmoid bone, and is called the ethmoidal fissure. 
The edges of the ethmoidal fissure are hollowed into cavities, which, by 
their union with the ethmoid bone, complete the ethmoidal cells: and, 
crossing these edges transversely, are two small grooves, sometimes canals, 
which open into the orbit by the anterior and posterior ethmoidal foramina. 
At the anterior termination of these edges are the irregular openings which 

* The internal surface of the left parietal bone. 1. The superior or sagittal border. 
'2. Hit' inferior, or squamous border. 3. The anterior, or coronal border. 4. The poste- 
rior, or lambdoidal border. 5. Part of the groove for the superior longitudinal sinus. 
*. 'ihe internal termination of the parietal foramen. 7. The anterior inferior angle of 
'he bone, on which is seen the groove for the trunk of the artorm meninges media. 8. 
the posterior inferior angle, upon which is seen a portion of the groove for the lateral 



FRONTAL BONE. 



63 



Fig. 26 * 




lead into the frontal sinuses ; and between the two internal angular pro- 
cesses, is a rough excavation which receives the nasal bones, and a pro- 
jecting process, the nasal spine. Upon each orbital plate, immediately 
beneath the external angular process, is a shallow depression which lodges 
the lachrymal gland ; and beneath the 
internal angular process a small pit, 
sometimes a tubercle, to which the 
cartilaginous pulley of the superior 
oblique muscle is attached. 

Internal Surface. — Along the mid- 
dle line of this surface is a grooved 
ridge, the edges of the ridge giving 
attachment to the falx cerebri and the 
groove lodging the superior longitu- 
dinal sinus. At the commencement 
of the ridge is an opening, sometimes 
completed by the ethmoid bone, the 
foramen caecum. This opening lodges 
a process of the dura mater, and oc- 
casionally gives passage to a small 
vein which communicates with the 
nasal veins. On each side of the vertical ridge are some slight depres- 
sions which lodge the glandulae Pacchioni, and on the orbital plates a 
number of irregular pits called digital fossce, which correspond with the 
convolutions of the anterior lobes of the cerebrum. The superior border 
is thick and strongly serrated, bevelled 
at the expense of the internal table in 
the middle, where it rests upon the 
junction of the two parietal, and at the 
expense of the external table on each 
side where it receives the lateral pres- 
sure of those bones. The inferior bor- 
der is thin, irregular, and squamous, 
and articulates with the sphenoid 
bone. 

Development. — By two centres, one 
for each lateral half. Ossification be- 
gins in the orbital arches, somewhat 
before the vertebra?. The two pieces 
are separate at birth, and unite by su- 
ture during the first year, the su- 
ture sometimes remaining permanent 

* The external surface of the frontal bone. 1. The situation of the frontal eminence 
of the right side. 2. The superciliary ridge. 3. The supra-orbital ridge. 4. The ex- 
ternal angular process. 5. The internal angular process. 6. The supra-orbital notch 
for the transmission of the supra-orbital nerve and artery; in the figure it is almost 
converted into a foramen by a small spiculum of bone. 7. The nasal tuberosity; the 
swelling around this point denotes the situation of the frontal sinuses. 8. The temporal 
ridge, commencing from the external angular process (4). The depression in which 
the figure 8 is situated is a part of the temporal fossa. 9. The nasal spine. 

f The internal surface of the frontal bone ; the bone is raised in such a manner as to 
show the orbito-nasal portion. 1. The grooved ridge for the lodgment of the superior 
longitudinal sinus and attachment of the falx. 2. The foramen caecum. 3. The superior 



Fig.27.f 




64 



TEMPORAL BONE. 



through life. The frontal sinuses make their appearance during the first 
year, and increase in size until old age. 

Articulations.— With twelve bones : the two parietal, the sphenoid, 
ethmoid, two nasal, two superior maxillary, two lachrymal, and two 

itir I t\ v 

Attachment of Muscles.— -To two pairs: corrugator supercilii, and tem- 
poral. 

Temporal Bone. — The temporal bone is situated at the side and base 

of the skull, and is divisible into a squamous, mastoid, and petrous portion. 

The Squamous portion, forming the anterior part of the bone, is thin, 

translucent, and contains no diploe. Upon its external surface it is 

smooth, to give attachment to the fleshy fibres of the temporal muscle, 

and has projecting from it an arched 
Fig. 28. ant j lengthened process, the zygoma. 

Near the commencement of the zygo- 
ma, upon its lower border, is a projec- 
tion called the tubercle, to which is at- 
tached the external lateral ligament of 
the lower jaw, and continued, horizon- 
tally inwards from the tubercle, a 
rounded eminence, the eminentia arti- 
cularis. The process of bone which 
is continued from the tubercle of the 
zygoma into the eminentia articularis 
is the inferior root of the zygoma. The 
superior root is continued upwards 
from the upper border of the zygoma, 
and forms the posterior part of the temporal ridge, serving by its projec- 
tion to mark the division of the squamous from the mastoid portion of the 
bone ; and the middle root is continued directly backwards, and termi- 
nates abruptly at a narrow fissure, the fissura Glaseri. The internal sur- 
face of the squamous portion is marked by several shallow fossae, which 
correspond with the convolutions of the cerebrum, and by a furrow for 

or coronal border of the bone; the figure is situated near that part which is bevelled at 
the expense of the internal table. 4. The inferior border of the bone. 5. The orbital 
plate of the left side. 6. The cellular border of the ethmoidal fissure. The foramen 
csReum (2) is seen through the ethmoidal fissure. 7. The anterior and posterior eth- 
moidal foramina; the anterior is seen leading into its canal. 8. The nasal spine. 9. The 
depression within the external angular process (12) for the lachrymal gland. 10. The 
depression for the pulley of the superior oblique muscle of the eye; immediately to 
the left of this number is the supra-orbital notch, and to its right the internal angular 
process. 11. The opening leading into the frontal sinuses: the leading line crosses the 
internal angular process. 12. The external angular process. The corresponding parts 
are seen on the other side of the figure. 

* The external surface of the temporal bone of the left side. 1. The squamous por- 
tion. 2. The mastoid portion. 3. The extremity of the petrous portion. 4. The zy- 
goma. 5. Indicates the tubercle of the zygoma, and at the same time its anterior root 
turning inwards to form the eminentia articularis. 6. The superior root of the zygoma, 
forming the posterior part of the temporal ridge. 7. The middle root of the zygoma, 
terminating abruptly at the glenoid fissure. 8. The mastoid foramen. 9. The meatus 
auditorius externus, surrounded by the processus auditorius. 10. The digastric fossa, 
situated immediately to the inner side of (2) the mastoid process. 1 1. The styloid 
process. 12. The vaginal process. 13. The glenoid or Glaserian fissure ; the leading 
line from this number crosses the rough posterior portion of the glenoid fossa. 14. The 
opening and part of the groove for the Eustachian tube. 




TEMPORAL BONE. 65 

the posterior branch of the arteria meningea media. The superior, or 
squamous border, is very thin, and bevelled at the expense of the inner 
surface, so as to overlap the lower and arched border of the parietal bone. 
The inferior border is thick, and dentated to articulate with the spinous 
process of the sphenoid bone. 

The Mastoid portion forms the posterior part of the bone ; it is thick,* 
and hollowed between its tables into a loose and cellular diploe. Upon 
its external surface it is rough for the attachment of muscles, and contrasts 
strongly w T ith the smooth and polished-like surface of the squamous por- 
tion : every part of this surface is pierced by small foramina, which give 
passage to minute arteries and veins ; one of these openings, oblique in 
its direction, of large size, and situated near the posterior border of the 
bone, the mastoid foramen, transmits a vein to the lateral sinus. This 
foramen is not unfrequently situated in the occipital bone. The inferior 
part of this portion is round and expanded, the mastoid process, and ex- 
cavated in its interior into numerous cells, which form a part of the organ 
of hearing. In front of the mastoid process, and between the superior 
and middle roots of the zygoma, is the large oval opening of the meatus 
auditorius externus, surrounded by a rough lip., the processus auditorius. 
Directly to the inner side of, and partly concealed by the* mastoid process, 
is a deep groove, the digastric fossa ; and a little more internally the oc- 
cipital groove, which lodges the occipital artery. Upon its internal sur- 
face the mastoid portion presents a broad and shallow' groove (fossa sig- 
moidea) for the lateral sinus, and terminating in this groove the internal 
opening of the mastoid foramen. The superior border of the mastoid por- 
tion is dentated ; and its posterior border, thick and less serrated, articu- 
lates with the inferior border of the occipital bone. 

The meatus auditorius externus is a slightly curved canal, somewhat 
more than half an inch in length, longer along its lower than its upper 
wall, and directed obliquely inwards and forwards. The canal is narrower 
at the middle than at each extremity, is broadest in its horizontal diameter, 
and terminates upon the outer wall of the tympanum by an abrupt oval 
border. Within the margin of this border is a groove for the insertion of 
the membrana tympani. 

The Petrous portion of the temporal bone is named from its extreme 
hardness and density. It is a three-sided pyramid, projecting horizontally 
forwards into the base of the skull, the base being applied against the in- 
ternal surface of the squamous and mastoid portions, and the apex being- 
received into the triangular interval between the spinous process of the 
sphenoid and the basilar process of the occipital bone. For convenience 
of description it is divisible into three surfaces — anterior, posterior, and 
basilar ; and three borders — superior, anterior, and posterior. 

Surfaces. — The anterior surface, forming the posterior boundary of the 
middle fossa of the interior of the base of the skull, presents for exami- 
nation from base to apex, first, an eminence caused by the projection of the 
perpendicular semicircular canal ; next, a groove leading to an irregular 
oblique opening, the hiatus Fallopii, for the transmission of the petrosal 
branch of the Vidian nerve; thirdly, another and smaller oblique foramen, 
immediately beneath the preceding, for the passage of the nervus petrosus 
superficialis minor, a branch of Jacobson's nerve ; and, lastly, a large 
foramen near the apex of the bone, the termination of the carotid 
canal. 

6* e 



66 



TEMPORAL BONE. 



Fig. 29* 




Fig. 30.t 



The posterior surface forms the front boundary of the posterior fossa of 
the base of the skull ; near its middle is the oblique entrance of the meatus 

auditorius internus. Above the meatus 
auditorius internus is a small oblique fis- 
sure, and a minute foramen ; the former 
lodges a process of the dura mater, and 
the foramen gives passage to a small vein. 
Further outwards, towards the mastoid 
portion of the bone, is a small slit, 
almost hidden by a thin plate of bone ; 
this is the aquceductus vestibuli, and 
transmits a small artery and vein of the 
vestibule and a process of dura mater. 
Below the meatus, and partly concealed 
by the margin of the posterior border of 
the bone, is the aquceductus cochlea, 
through which passes a vein from the cochlea to the internal jugular vein, 
and a process of dura mater. 

• The meatus auditorius internus is about one-third of an inch in depth, 
and pursues a slightly oblique course in relation to the petrous portion of 

the temporal bone, but a course directly out- 
wards in relation to the cranium. At the bot- 
tom of the meatus, and upon its anterior as- 
pect, is a reniform fossa, the concave border 
of which is directed towards the entrance of 
the meatus. The reniform fossa is divided 
into an upper and lower compartment by a 
sharp ridge, which is prolonged for some dis- 
tance upon the anterior wall of the meatus, 
and sometimes as far as its aperture ; in either 
case it marks the situation of the two nerves, 
facial and auditory, which constitute the se- 
venth pair, and enter the meatus. Along the convexity of the reniform 
fossa, and arranged in a curved line from above downwards, are four or 

* The left temporal bone, seen from within. 1. The squamous portion. 2. The 
mastoid portion. The number is placed immediately above the inner opening of the 
mastoid foramen. 3. The petrous portion. 4. The groove for the posterior branch of 
the artena meningea media. 5. The bevelled edge of the squamous border of the bone. 
6. The zygoma. 7. The digastric fossa immediately internal to the mastoid process 
8. The occipital groove. 9. The groove for the lateral sinus. 10. The elevation upon 
the anterior surface of the petrous bone marking the situation of the perpendicular semi- 
circular canal. 11. The opening of termination of the carotid canal. 12. The meatus 
auditorius internus. 13. A dotted line leads upwards from this number to the narrow- 
fissure which lodges a process of the dura mater. Another line leads downwards to 
the sharp edge which conceals the opening of the aquaeductus cochleae, while the num- 
ber itself is situated on the bony lamina which overlies the opening of the aquseductus 
vestibuli. 14. The styloid process. 15. The stylo-mastoid foramen. 16. The carotid 
foramen. 17. The jugular process. The deep excavation to the left of this process 
forms part of the jugular fossa, and that to the right is the groove for the eighth pair of 
nerves. IS. The notch for the fifth nerve upon the upper border of the petrous bone, 
near its apex. 19. The extremity of the petrous bone which gives origin to the levator 
palati and tensor tympani muscles. 

tA. The reniform fossa of the meatus auditorius internus; right temporal bone. 
I. The ridge dividing the reniform fossa into two compartments. 2. The opening of 
the aqua'ductus Fallopii. The openings following that of the aquceductus Fallopii in 
a curved direction require no reference. 3. The cluster of three or four oblique 




TEMPORAL BONE. 67 

five openings, the two upper ones being the largest, and occupying the 
superior compartment of the reniform fossa, and the two or three interior 
ones, smaller than the upper, the inferior compartment. Behind the 
latter, at the distance of a line and a half, and on the posterior wall of the 
meatus, is a cluster of three or four oblique openings, two of which are 
minute. The inferior and larger compartment of the reniform fossa pre- 
sents a well-marked spiral groove, which commences on the convex border 
of the fossa, immediately below the line of openings above described, and, 
sweeping round the convexity of the inferior compartment, and becoming 
deeper as it proceeds, terminates by a small round aperture in the centre 
of the spire. The uppermost of the openings of the reniform fossa is the 
aperture of the aquaeductus Fallopii, and gives passage to the facial nerve. 
The rest are cul de sacs, pierced at the bottom by a number of minute 
foramina for the passage of filaments of the vestibular nerve, while the 
cluster of three openings on the posterior wall of the meatus are intended 
for single filaments of the same nerve. The spiral groove corresponds 
with the base of the cochlea, and being pierced by a number of minute 
foramina for filaments of the cochlear nerve, is named tractus spiralis 
foraminulentus. The opening in the centre of the spiral impression leads 
into a canal which occupies the central axis of the modiolus, and is thence 
called tubulus centralis modioli. 

The basilar surface is rough and irregular, and enters into the formation 
of the under surface of the base of the skull. Projecting downwards, near 
its middle, is a long sharp spine, the styloid process, occasionally connected 
with the bone only by cartilage, and lost during maceration, particularly 
in the young subject. At the base of this process is a rough sheath-like 
ridge, into which the styloid process appears implanted, the vaginal pro- 
cess. In front of the vaginal process is a broad triangular depression, the 
glenoid fossa, bounded in front by the eminentia articularis, behind by 
the vaginal process, and externally by the rough lip of the processus audi- 
torius. 

This fossa is divided transversely by the glenoid fissure (fissura Glaseri), 
which lodges the extremity of the processus gracilis of the malleus, and 
transmits the laxator tympani muscle, chorda tympani nerve, and anterior 
tympanic artery. The surface of the fossa in front of this fissure is smooth, 
to articulate with the condyle of the lower jaw ; and that behind the fissure 
is rough, for the reception of a part of the parotid gland. At the extre- 
mity of the inner angle of the glenoid fossa is the foramen of the Eusta- 
chian tube ; and separated from it by a thin lamella of bone, called pro- 
cessus cochleariformis, a small canal for the transmission of the tensor 
tympani muscle. Directly behind, and at the root of the styloid process, 
is the stylo-ma stoid foramen, the opening of exit of the facial nerve, and 
of entrance of the stylo-mastoid artery. Nearer the apex of the bone is a 

openings on the posterior wall of the meatus. 4. The spirally-grooved base of the 
cochlea. 

b. A section of the temporal bone, right side, showing the curved direction of the 
meatus auditorius externus. 1. The edge of the processus auditorius. 2. The groove 
into which the membrana tympani is inserted. The obliquity of the line from 2 to 3 
indicates the oblique termination of the meatus, and the consequent oblique direction 
of the membrana tympani. 4, 4. The cavity of the tympanum. 5. The opening of 
the Eustachian tube. 6. Part of the aquaeductus Fallopii. 7. Part of the carotid 
canal. 

c. The annulus membrana? tympani or temporal bone of the foetal skull, right side. 



68 TEMPORAL BONE. 

large oval opening, the carotid foramen, the commencement of the carotid 
canal, which lodges the internal carotid artery and the carotid plexus. 
And between the stylo-mastoid and carotid foramen, in the posterior 
border, is an irregular excavation forming part of the jugular fossa for the 
commencement of the internal jugular vein. The proportion of the jugular 
fossa formed by the petrous portion of the temporal bone is very different 
in different bones ; but in all, the fossa presents a vertical ridge on its 
inner side, which cuts off" a small portion from the rest. The upper part 
of this ridge forms a spinous projection, which is called the jugular process, 
the groove to the inner side of the ridge lodges the eighth pair of nerves, 
and the lower part of the ridge is the septum of division between the jugu- 
lar fossa and the carotid foramen. Upon this portion of the ridge near the 
posterior margin of the carotid foramen is a small opening leading into a 
canal, which transmits the tympanic branch (Jacobson's nerve) of the 
glossopharyngeal nerve. Between the jugular fossa and the stylo-mastoid 
foramen is another small opening leading into the canal for the passage of 
the auricular branch of the pneumogastric nerve. 

Borders. — The superior bo rder is sharp, and gives attachment to the 
tentorium cerebelli. It is grooved for the superior petrosal sinus, and 
near its extremity is marked by a smooth notch upon which reclines the 
fifth nerve. 

The anterior border is grooved for the Eustachian tube, and forms the 
posterior boundary of the foramen lacerum basis cranii ; by its sharp 
extremity it gives attachment to the tensor tympani and levator palati 
muscles. The posterior border is grooved for the inferior petrosal sinus, 
and excavated for the jugular fossa; it forms the anterior boundary of the 
foramen lacerum posterius. 

Development. — By Jive centres : one for the squamous portion, one for 
the mastoid process, one for the petrous portion, one for the auditory pro- 
cess, which in the fetus is a mere bony ring, incomplete superiorly, and 
serving for the attachment of the membrana tympani, annulus membrana 
tympani ; and one for the styloid process. Ossification occurs in these 
pieces in the following order: in the squamous portion immediately after 
the vertebra, then in the petrous, tympanic, mastoid, and styloid. The 
tympanic ring is united by its extremities to the squamous portion during 
the last month of intra-uterine life ; the squamous, petrous, and mastoid 
portions are consolidated during the first year ; and the styloid some years 
after birth. It not unfrequently happens that the latter remains perma- 
nently separate, or is prolonged by a series of pieces to the os hyoides, 
and so completes the hyoid arch. The subsequent changes in the bone 
are the increase of size of the glenoid fossa, the growth of the meatus 
auditonus externus, the levelling of the "surfaces of the petrous portion, 
and the development of mastoid cells. Traces of the union of the petrous 
w i tli the squamous portion of the bone are usually perceptible in the adult. 

Articulations.— With Jive bones : occipital, parietal, sphenoid, inferior 
maxillary, and malar. 

Attachment of Muscles.— -To fourteen : by the squamous portion to the 
temporal ; by the zygoma, to the masseter ; by the mastoid portion to 
the occipito-frontahs, splenius capitis, sterno-mastoid, trachelo-mastoid 
digastncus and retrahens aurem ; by the styloid process, to the stylo- 
phuiyngeus, stylo-hyoideus, stylo-glossus, and two ligaments the stylo- 



SPHENOID BO^NE. 69 

hyoid and stylo-maxillary ; and by the petrous portion, to the levator 
palati, tensor tympani, and stapedius. 

Sphenoid Bone. — The sphenoid (acpr,v, a wedge) is an irregular bone 
situated at the base of the skull, wedged between the other bones of the 
cranium, and entering into the formation both of the cranium and face. It 
bears some resemblance, in form, to a bat with its wings extended, and is 
divisible into body, wings, and processes. 

The body forms the central mass of the bone, from which the wings and 
processes are projected. From the upper and anterior part of the body 
extend on each side two small triangular plates — the lesser wings ; from 
either side and expanding laterally are the greater wings ; proceeding 
backwards from the base of the greater wings, the spinous processes, and 
downwards, the pterygoid processes. 

The body presents for examination a superior or cerebral surface, an 
antero-inferior surface, and a posterior surface. 

Superior Surface. — At the anterior extremity of this surface is a small 
projecting plate, the ethmoidal spine, and spreading out on either side the 
lesser wings. Behind the ethmoidal spine in the middle line is a rounded 
elevation, the olivary process, which supports the commissure of the optic 
nerves ; and on either side of the posterior margin of this process is a 
tubercle, the middle clinoid process. Passing outwards and forwards from 
the olivary process, are the optic foramina, which transmit the optic nerves 
and ophthalmic arteries. Behind the optic foramina are two sharp tuber- 
cles, the anterior clinoid processes, which are the inner terminations of the 
lesser wings. Beneath these processes, on the sides of the olivary process, 
are two depressions* for the last turn of the internal carotid arteries. Be- 
hind the olivary process is the sella turcica (ephippium), the deep fossa 
which lodges the pituitary gland and circular sinus ; behind and somewhat 
overhanging the sella turcica, is a broad rough plate (dorsum ephippii) 
bounded at each angle by a tubercle, the posterior clinoid processes ; and 
behind this plate an inclining surface (clivus Blumenbachii), which is con- 
tinuous with the basilar process of the occipital bone. On either side of 
the sella turcica is a broad 

groove {carotid) which lodges Flg - 31 t 

the internal carotid artery, the ^g^v^ yj^Gl^\ 

cavernous sinus, and the orbi- f^^^^l^ J ^^^^^k 

nal to this groove, at the June- w| £.-,■ '-? : ^^^ ^^ % /, jJKfll B^/ 

tion of the greater wings with \> * J ^R^l'*3Rp- : §f§* 

the sphenoidal fissure, which ^@S»JniP^^^I6v^g 

separates the greater and lesser y V* ^ *sS 

wings, and transmits the third, 

* These depressions are occasionally, as in a skull before me, converted into fora 
mina by the extension of a short bony pillar from the middle to the anterior clinoid 
process. 

\ The superior or cerebral surface of the sphenoid bone. 1. The processus olivaris. 
2. The ethmoidal spine. 3. The lesser wing of the left side. 4. The cerebral surface 
of the greater wing of the same side. 5. The spinous process. 6. The extremity of 
the pterygoid process of the same side, projecting downwards from the under surface 
of the body of the bone. 7. The foramen opticum. 8. The anterior clynoid process. 



70 SPHENOID BONE. 



• 



fourth, the three branches of the ophthalmic division of the fifth and the 
sixth nerves, and the ophthalmic vein. Behind and beneath this fissure 
is the foramen rotundum for the superior maxillary nerve ; and still farther 
back, in the base of the spinous process, the foramen ovale for the inferior 
maxillary nerve, arteria meningea parva, and nervus petrosus superficialis 
minor. Behind the foramen ovale, near the apex of the spinous process, 
is the foramen spinosum for the arteria meningea medea. 

Upon the anteroinferior surface of the sphenoid is a long flattened 
spine or crest, the superior part of which, crista sphenoidalis, articulates 
with the central lamella of the ethmoid, while the inferior part longer and 
sharper, the rostrum sphenoidale, is intended to be inserted into the sheath 
formed by the upper border of the vomer. On either side of the crista 
sphenoid alis is an irregular opening leading into the sphenoidal cells. 
The sphenoidal cells, which are absent in the young subject, are divided 
by a median septum which is continuous with the crista, and are partially 
closed by two thin plates of bone (frequently broken away), % the sphenoidal 
spongy bones. On each side of the sphenoidal cells are the outlets of the 

optic foramina, sphenoidal fissures, 
Flg - 32 -* and foramina' rotunda, the lesser 

and greater wings ; and, below, the 
pterygoid processes. Upon the un- 
der surface of the body are two thin 
plates of bone (processus vaginales) 
proceeding from the base of the 
pterygoid process at each side, and 
intended for articulation with the 
borders of the vomer. On each of 
these plates, close to the root of 
the pterygoid process, is a groove 
(sometimes a complete canal) converted into a canal by the palate bone, 
the ptery go-palatine canal for the ptery go-palatine artery ; and traversing 
the roots of the pterygoid processes at their union with the body of the 

9. The groove by the side of the sella turcica; for lodging the internal carotid artery, 
cavernous plexus, cavernous sinus, and orbital nerves. 10. The sella turcica; the two 
tubercles in front of the figure are the middle clinoid processes. 11. The posterior 
boundary of the sella turcica; its projecting angles are the posterior clinoid processes. 
12. The basilar portion of the bone. 13. Part of the sphenoidal fissure. 14. The fora- 
men rotundum. 15. The foramen ovale. 16. The foramen spinosum. 17. The angu- 
lar interval which receives the apex of the petrous portion of the temporal bone. The 
posterior extremity of the Vidian canal terminates at this angle. 18. The spine of the 
spinous process; it affords attachment to the internal lateral ligament of the lower jaw. 
19. The border of the greater wing and spinous process, which articulates with the 
anterior part of the squamous portion of the temporal bone. 20. The internal border 
of the spinous process, which assists in the formation of the foramen lacerum basis 
cranii. 21. That portion of the greater ala which articulates with the anterior inferior 
angle of the parietal bone. 22. The portion of the greater ala which articulates with 
the orbital process of the frontal bone. 

* The anteroinferior view of the sphenoid bone. 1. The ethmoid spine. 2. The 
rostrum. 3. The sphenoidal spongy bone, partly closing the left opening of the sphe- 
noidal cells. 4. The lesser wing. 5. The foramen opticum, piercing the base of the 
lesser wing. 6. The sphenoidal fissure. 7. The foramen rotundum. 8. The orbital 
surface of the greater wing. 9. Its temporal surface. 10. The pterygoid ridge. 11. 
The pterygo-palatine canal. 12. The foramen of entrance to the Vidian canal! 13. 
The internal pterygoid plate. 14. The hamular process. If). The external pterygoid 
plate. If.. The foramen spinosum. 17. The foramen ovale. IS. The extremity of 
the spinous process of the sphenoid. 




SPHENOID BONE. 71 

bone, are the two pterygoid or Vidian canals, which give passage to the 
Vidian nerve and artery at each side. 

The posterior surface is flat and rough, and articulates with the basilar 
process of the occipital bone. In the adult this union is usually completed 
by bone; from which circumstance the sphenoid, in conjunction with the 
occipital, is described by Soemmering and Meckel as a single bone, under 
the name of spheno-occipital. The posterior surface is continuous on 
each side with the spinous process, and at the angle of union is the termi- 
nation of the Vidian canal. 

The lesser wings (processes of Ingrassias) are thin and triangular, the 
base being attached to the upper and anterior part of the body of the sphe- 
noid, and the apex extended outwards, and terminating in an acute point. 
The anterior border is irregularly serrated, the posterior being free and 
rounded, and received into the fissure of Sylvius of the cerebrum. The 
inner extremily of this border is the anterior clinoid process, which is sup- 
ported by a short pillar of bone, giving attachment to a part of the com- 
mon tendon of the muscles of the orbit. The lesser wing forms the pos- 
terior part of the roof of the orbit, and its base is traversed by the optic 
foramen. 

The greater wings present three surfaces ; a superior or cerebral, which 
forms part of the middle fossa of the base of the skull, an anterior surface 
which assists in forming the outer wall of the orbit, and an external sur- 
face divided into two parts by the pterygoid ridge. The superior part of 
the external surface enters into the formation of the temporal fossa, and the 
inferior portion forms part of the zygomatic fossa. The pterygoid ridge, 
dividing the two, gives attachment to the upper origin of the pterygoideus 
externus muscle. 

The spinous processes project backwards at each side from the base of 
the greater wings of the sphenoid, and are received into the angular inter- 
vals between the squamous and petrous portions of the temporal bones. 
Piercing the base of each process is a large oval opening, the foramen 
ovale; nearer its apex a smaller opening, the foramen spinosum; and 
extending downwards from the apex a short spine, which gives attachment 
to the internal lateral ligament of the lower jaw and to the laxator tym- 
pani muscle. The external border of the spinous process is rough, to 
articulate with the lower border of the squamous portion of the temporal 
bone ; the internal forms the anterior boundary of the foramen lacerum 
basis cranii, and is somewhat grooved for the reception of the Eustachian 
tube. 

The pterygoid processes descend perpendicularly from the base of the 
greater wings, and form in the articulated skull the lateral boundaries of 
the posterior nares. Each process consists of an external and internal 
plate, and an anterior surface. The external plate is broad and thin, 
giving attachment, by its external surface, to the external pterygoid 
muscle, and by its internal surface to the internal pterygoid. This plate 
is sometimes pierced by a foramen, which is not unfrequently formed by 
a process of communication passing between it and the spinous process. 
The internal pterygoid plate is long and narrow, and terminated at its 
extremity by a curved hook, the hamular process, around which plays the 
tendon of the tensor palati muscle. At the base of the internal pterygoid 
plate is a small oblong depression, the scaphoid fossa, from which arises 
the circumflexus or tensor palati muscle. The interval between the two 



72 ETHMOID BONE. 

pterygoid plates is the pterygoid fossa; and the two plates are separated 
interiorly by an angular notch (palatine), which receives the tuberosity, or 
pterygoid process, of the palate bone. The anterior surface of the ptery- 
goid process is broad near its base, and supports Meckel's ganglion. The 
base of the process is pierced by the Vidian canal. 

Development — By twelve centres : four for the body, viz. two for its 
anterior (spheno-orbital), and two for its posterior part (spheno-temporal); 
four for the four wings ; two for the internal pterygoid plates, and two for 
the sphenoidal spongy bones. Ossification commences in the various 
pieces of the sphenoid in the following order : — greater ala?, at about the 
same time with the other bones of the cranium ; lesser alse and posterior 
body, at the end of the second month ; anterior body at the end of the 
third ; internal pterygoid plate and spongy bones, between the period of 
birth and the second year. Osseous union occurs first between the centres 
for the posterior body, and at about the same time between each centre of 
the anterior body and its corresponding (lesser) ala ; the third union takes 
place between the internal pterygoid plate and the greater ala ; the fourth 
between the two centres of the anterior body, and at the same time be- 
tween the anterior and posterior body. This is the state of union at birth, 
the bone consisting of five centres, one being the body and lesser alae ; 
one, on each side, the great ala and internal pterygoid plate ; and the 
remaining two the sphenoidal spongy bones. The greater alae unite with 
the body during the first year ; the spongy bones after puberty ; and the 
body of the sphenoid with the basilar process of the occipital bone be- 
tween eighteen and twenty-five. 

Articulations. — With twelve bones ; that is, with all the bones of the 
head, and five of the face, viz. the two malar, two palate, and the vomer. 

Attachment of Muscles. — To twelve pairs : temporal, external ptery- 
goid, internal pterygoid, superior constrictor, tensor palati, laxator tym- 
pani, levator palpebral, obliquus superior, superior rectus, internal rectus, 
inferior rectus, and external rectus. 

Ethmoid Bone. — The ethmoid (Mp&§, a sieve) is a square-shaped cel- 
lular bone, situated between the two orbits, at the root of the nose, and 
perforated upon its upper surface by a number of small openings, from 
which peculiarity it has received its name. It consists of a perpendicular 
lamella and two lateral masses. 

The perpendicular lamella is a thin central plate, which articulates with 
the vomer and cartilage of the septum, and assists in forming the septum 
of the nose. It is surmounted superiorly by a thick and strong process, 
the crista galli, which projects into the cavity of the skull, and gives 
attachment to the falx cerebri. From the base of the anterior border of 
this process there project forward two small plates, alar processes, which 
are received into corresponding depressions in the frontal bone, and often 
complete posteriorly the foramen caacum. On each side of the crista galli, 
upon the upper surface of the bone, is a thin and grooved plate perforated 
by a number of small openings, the cribriform lamella, which supports the 
bulb of the olfactory nerve, and gives passage to its filaments, and to the 
nasal branch of the ophthalmic nerve. In the middle of the groove of 
this lamella the foramina pierce the bone completely, but at either side 
they are the apertures of canals, which run for some distance in the 
substance of the central lamella, inner wall of the lateral mass, and spongy 




ETHMOID BONE. 73 

bones. The opening for the nasal nerve is a nar- Fig. 33 * 

row slit in the anterior part of the cribriform la- 
mella, close to the crista galli. The cribriform 
lamella serves to connect the lateral masses with 
the perpendicular plate. 

The lateral masses (labyrinthi) are divisible 
into an internal and external surface, and four 
borders, superior, inferior, anterior, and posterior. 
The internal surface is rough and slightly convex, 
and forms the external boundary of the upper part 
of the nasal fossae. Towards the posterior border 
of this surface is a narrow horizontal fissure, the 
superior meatus of the nose, the upper margin of which is thin, and 
somewhat curled inwards ; hence it is named the superior turbinated bone 
(concha superior). Below the meatus is the convex surface of another 
thin plate, w T hich is curled outwards, and forms the lower border of the 
mass, the middle turbinated bone (concha media). The external surface 
is quadrilateral and smooth, hence it is named os planum, and, from its 
thinness, lamina papyracea ; it enters into the formation of the inner wall 
of the orbit. 

The superior border is irregular and cellular, the cells being completed 
by the edges of the ethmoidal fissure of the frontal bone. This border is 
crossed by two grooves, sometimes complete canals, opening into the 
orbit by the anterior and posterior ethmoidal foramina. The inferior bor- 
der is formed internally by the lower border of the middle turbinated bone, 
and externally by a concave irregular fossa, the upper boundary of the 
middle meatus. The anterior border, presents a number of incomplete 
cells, which are closed by the superior maxillary and lachrymal bone ; and 
the posterior border is regularly cellular, to articulate with the sphenoid 
and palate bones. 

The lateral masses are composed of cells, which are divided by a thin 
partition into anterior and posterior ethmoidal cells. The anterior, the 
most numerous, communicate with the frontal sinuses, and open by means 
of an irregular and incomplete tubular canal, the infundibulum, into the 
middle meatus. The posterior calls, fewer in number, open into the su- 
perior meatus. 

Development. — By three centres : one for each lateral mass, and one for 
the perpendicular lamella. Ossification commences in the lateral masses 
at about the beginning of the fifth month, appearing first in the os planum 
and then in the spongy bones. During the latter half of the first year 
after birth, the central lamella and lamina cribrosa begin to ossify, and are 
united to the lateral masses by the beginning of the second year. The 
cells of the ethmoid are developed in the course of the fourth and fifth year. 

* The ethmoid bone seen from above and behind. 1. The central lamella'. 2, 2. The 
lateral masses ; the numbers are placed on the posterior border of the lateral mass at 
each side. 3. The crista galli process. 4. The cribriform plate of the left side, pierced 
by its foramina. 5. The hollow space immediately above and to the left of this num- 
ber is the superior meatus. 6. The superior turbinated bone. 7. The middle turbinated 
bone ; the numbers 5, 6. 7. are situated upon the internal surface of the left lateral mass, 
near its posterior part. The interval between these parts is the superior meatus. 8. The 
external surface of the lateral mass, or os planum. 9. The superior or frontal border 
of the lateral mass, grooved by the anterior and posterior ethmoidal canals. 10. Refers 
to the concavity of the middle turbinated bone, which is the upper boundary of the 
middle meatus. 

7 



74 



SUPERIOR MAXILLARY BONES. 



Articulations. — With thirteen bones : two of the cranium, — the frontal 
and sphenoid ; the rest of the face, viz. the nasal, superior maxillary, la- 
chrymal, palate, the inferior turbinated, and the vomer. 

No muscles are attached to this bone. 



BONES OF THE FACE. 

The face is composed of fourteen bones ; viz. the 
Two nasal, Two palate, 

Two superior maxillary, Two inferior turbinated, 

Two lachrymal, Vomer, 

Two malar, Inferior maxillary. 

Nasal Bones. — The nasal (fig. 39) are two small quadrangular bones, 
forming by their union the bridge and base of the nose. Upon the upper 
surface they are convex, and pierced by a foramen for a small artery ; on 
the under surface they are somewhat concave, and marked by a groove, 
which lodges the nasal branch of the ophthalmic nerve. The superior 
border is narrow and thick, the inferior broad, thin, and irregular. 

Development. — By a single centre for each bone, the first ossific depo- 
sition making its appearance at the same time as in the vertebrae. 

Articulations. — With Jour bones : frontal, ethmoidal, nasal, and supe- 
rior maxillary. 

Attachment of Muscles. — It has in relation with it the pyramidalis nasi, 
and compressor nasi ; but neither of these muscles is inserted into it. 

Superior Maxillary Bones. — The superior maxillary are the largest 
bones of the face, with the exception of the lower jaw ; they form, by their 
union, the whole of the upper jaw, and assist in the construction of the 
nose, the orbit, the cheek, and the palate. Each bone is divisible into a 
body and four processes. 

The body is triangular in form, and hollowed in 
its interior into a large cavity, the antrum maxillare 
(antrum of Highmore). It presents for examina- 
tion four surfaces, external or facial, internal or 
nasal, posterior or zygomatic, and superior or 
orbital. 

The external , or facial surface, forms the anterior 
part of the bone ; it is irregularly concave, and 
presents a deep depression towards its centre, the 
canine fossa, which gives attachment to two mus- 
cles, the compressor nasi and levator anguli oris. 
Immediately above this fossa is the infra-orbital 
foramen, the termination of the infra-orbital canal, 
transmitting the superior maxillary nerve and infra- 
orbital artery; and above the infra-orbital foramen, 

* The superior maxillary bone of the right side, as seen from the lateral aspect. 1. 
The external or facial surface ; the depression in which the figure is placed is the canine 
fossa. 2. The posterior, or zygomatic surface. 3. The superior or orbital surface. 4. 
The infra-orbital foramen ; it is situated immediately below the number. 5. The infra- 
orbital canal, leading to the infra-orbital foramen. f>. The inferior border of the orbit. 
7. The malar process. 8. The nasal process. 9. The concavity forming the lateral 
boundary of the anterior nares. 10. The nasal spine. 11. The incisive, or mvrtiform 
lossa. 12. The alveolar process. 13. The internal border of the orbital surface, which 
articulates with the ethmoid and palate bone. 14. The concavity which articulates with 



Fig. 34* 




SUPERIOR MAXILLARY BONES. 75 

the lower margin of the orbit, continuous externally with the rough articu- 
lar surface of the malar process, and internally with a thick ascending plate, 
the nasal process. Towards the middle line of the face this surface is 
bounded by the concave border of the opening of the nose, which is pro- 
jected forwards at its inferior termination into a sharp process, forming, 
with a similar process of the opposite bone, the nasal spine. Beneath the 
nasal spine, and above the two superior incisor teeth, is a slight depression, 
the incisive, or myrh 'form fossa , which gives origin to the depressor labii 
superioris alaeque nasi muscle. The myrtiform fossa is divided from the 
canine fossa by a perpendicular ridge, corresponding with the direction 
of the root of the canine tooth. The inferior boundary of the facial surface 
is the alveolar process which contains the teeth of the upper jaw ; and it 
is separated from the zygomatic surface by a strong projecting eminence, 
the malar process. 

The internal, or nasal surface, presents a large irregular opening, lead- 
ing into the antrum maxillare ; this opening is nearly closed in the articu- 
lated skull by the ethmoid, palate, lachrymal, and inferior turbinated bones. 
The cavity of the antrum is somewhat triangular, corresponding in shape 
with the form of the body of the bone. Upon its inner wall are numerous 
grooves, lodging branches of the superior maxillary nerve, and projecting 
into its floor several conical processes, corresponding with the roots of the 
first and second molar teeth. In front of the opening of the antrum is the 
strong ascending plate of the nasal process, marked inferiorly by a rough 
horizontal ridge (crista turbinalis inferior), which gives attachment to the 
inferior turbinated bone. The concave depression immediately above this 
ridge corresponds with the middle meatus of the nose, and that below the 
ridge with the inferior meatus. Between the nasal process and the opening 
of the antrum, is a deep vertical groove (sulcus lachrymalis) which is con- 
verted into a canal by the lachrymal and inferior turbinated bone, and consti- 
tutes the nasal duct. The superior border of the nasal surface is irregularly 
cellular, and articulates with the lachrymal and ethmoid bone : the poste- 
rior border is rough, and articulates with the palate bone ; the anterior 
border is sharp, and forms the free margin of the opening of the nose ; and 
from the inferior border projects inwards a strong horizontal plate, the 
palate process. 

The posterior surface may be called zygomatic, from forming part of 
the zygomatic fossa ; it is bounded externally by the malar process, and 
internally by a rough and rounded border, the tuberosity, which is pierced 
by a number of small foramina (foramina alveolaria posteriora), giving 
passage to the posterior dental nerves and branches of the superior dental 
artery. The lower part of this tuberosity presents a rough oval surface, to 
articulate with the palate bone, and immediately above and to the inner 
side of this articular surface a smooth groove, which forms part of the pos- 
terior palatine canal. The superior border is smooth and rounded to form 
the lower boundary of the spheno-maxillary fissure, and is marked by a 
notch, the commencement of the infra-orbital canal. The inferior boundary 
is the alveolar process, containing the last two molar teeth. 

The orbital surface is triangular and thin, and constitutes the floor of 
the orbit. It is bounded internally by an irregular edge, which articulates 

the lachrymal bone, and forms the commencement of the nasal duct. 15. The crista 
nasalis of the palate process, i. The two incisor teeth, c. The canine, b. The two 
bicuspidati. m. The three molares. 



76 SUPERIOR MAXILLARY BONES. 

with the palate, ethmoid, and lachrymal bone ; posteriorly, by the smooth 
border which enters into the formation of the spheno-maxillary fissure ; 
and, anteriorly, by a convex margin, partly smooth and partly rough, the 
smooth portion forming part of the lower border of the orbit, and the 
rough articulating with the malar bone. The middle of this surface is 
channelled by a deep groove and canal, the infra-orbital, which termi- 
nates at the infra-orbital foramen ; and near the root of the nasal process 
is a slight depression, marking the origin of the inferior oblique muscle of 
the eyeball. 

The four processes of the superior maxillary bone are the nasal, malar, 
alveolar, and palate. 

The nasal process ascends by the side of the nose, to which it forms the 
lateral boundary, and articulates with the frontal and nasal bone. By its 
external surface it gives attachment to the levator labii superioris aleeque 
nasi, and to the orbicularis palpebrarum muscle. Its internal surface con- 
tributes to form the inner wall of the nares, and is marked transversely by 
a horizontal ridge (crista turbinalis superior) which divides it into two 
portions, one above the ridge, irregular and uneven, forgiving attachment 
to and completing the cells of the lateral mass of the ethmoid ; the other 
below, smooth and concave, corresponding with the middle meatus. The 
posterior border is thick, and hollowed into a groove for the nasal duct. 
The margin of the nasal process, which is continuous with the lower 
border of the orbit, is sharp and marked by a small tubercle which serves 
as a guide to the introduction of the knife in the operation for fistula 
lachrymalis. 

The malar process ', large and irregular, is situated at the angle of sepa- 
ration between the facial and zygomatic surfaces, and presents a triangular 
surface for articulation with the malar bone. 

The alveolar process forms the lower margin of the bone ; it is spongy 
and cellular in texture, and excavated into deep holes for the reception 
of eight teeth. 

The palate process is thick and strong, and projects horizontally inwards 
from the inner surface of the body of the bone. Superiorly, it is concave 
and smooth, and forms the floor of the nares ; inferiorly, it is also concave 
but uneven, and assists in the formation of the roof of the palate. This 
surface is marked by a deep groove, which lodges the posterior palatine 
nerve and artery. Its internal edge is raised into a ridge (crista nasalis), 
which, with a corresponding ridge in the opposite bone, forms a groove 
for the reception of the vomer. The prolongation of this ridge forwards 
beyond the level of the facial surface of the bone is the nasal spine. At 
the anterior extremity of its nasal surface is a foramen, which leads into a 
canal formed conjointly by the two superior maxillary bones, the anterior 
palatine canal. The termination of this canal is situated immediately 
behind the incisor teeth, hence it is also named the incisive foramen. 
Associated with the incisive openings and canal are two smaller canals, 
the naso-palatine, which transmit the naso-palatine nerves. These canals 
are situated in the walls of the incisive canal, and terminate inferiorly in 
that canal, either by separate openings or conjoined. 

Development.— By four centres : one for the anterior part of the palate, 
and incisive portion of the alveolar process (the permanence of this piece 
constitutes the intermaxillary bone of animals) ; one for that portion of the 
bone lying internally to the infra-orbital canal and foramen ; one for that 



LACHRYMAL AND MALAR BONES. 77 

portion lying externally to the infra-orbital groove and canal ; and one 
for the palate process. The superior maxillary bone is one of the earliest 
to show signs of ossification, this process beginning in the alveolar pro- 
cess, and being associated with the early development of teeth. The 
early development of the alveolar process, and the consequent fusion at 
this point of the original pieces, explains the difficulties which have been 
felt by anatomists in determining the precise number of the ossifying cen- 
tres of this bone. 

Articulations. — With nine bones; viz. with two of the cranium, and 
with all the bones of the face, excepting the inferior maxillary. These 
are, the frontal and ethmoid ; nasal, lachrymal, malar, inferior turbinated, 
palate, vomer, and its fellow of the opposite side. 

Attachment of Muscles. — To nine; orbicularis palpebrarum, obliquus 
inferior oculi, levator labii superioris alseque nasi, levator labii superioris 
proprius, levator anguli oris, compressor nasi, depressor labii superioris 
alseque nasi, buccinator, masseter. 

Lachrymal Bones (os unguis, from an imagined resemblance to a 
finger-nail). — The lachrymal is a thin oval-shaped plate of bone, situated 
at the anterior and inner angle of the orbit. It may be Fi 35# 
divided into an external and internal surface and four bor- 
ders. The external surface is smooth and marked by a ver- 
tical ridge, the lachrymal crest, into two portions, one of 
which is flat and enters into the formation of the orbit, hence 
may be called the orbital portion ; the other is concave, and 
lodges the lachrymal sac, hence, the lachrymal portion. 
The crest is expanded inferiorly into a hook-shaped process 
(hamulus lachrymalis), which forms part of the outer boundary 
of the fossa lachrymalis. The internal surface is uneven, and completes 
the anterior ethmoid cells ; it assists also in forming the wall of the nasal 
fossae and nasal duct. The four borders articulate with adjoining bones. 

Development. — By a single centre, appearing in the early part of the 
third month. 

Articulations. — With four bones : two of the cranium, frontal and 
ethmoid ; and two of the face, superior maxillary and inferior turbinated 
bone. 

Attachment of Muscles. — To one muscle, the tensor tarsi, and to an 
expansion of the tendo oculi, the former, arising from the orbital surface, 
the other being attached to the lachrymal crest. 

Malar Bones (mala, the cheek). — The malar (fig. 39) is the strong quad- 
rangular bone which forms the prominence of the cheek. It is divisible 
into an external and internal surface and four processes, the frontal, orbital, 
maxillary, and zygomatic. The external surface is smooth and convex, 
and pierced by several small openings which give passage to filaments of 
the temporo-malar nerve and minute arteries. The internal surface is 

* The lachrymal bone of the right side, viewed upon its external or orbital surface. 
1. The orbital portion of the bone. 2. The lachrymal portion; the prominent ridge 
between these'two portions is the crest. 3. The lower termination of the crest, the 
hamulus lachrymalis. 4. The superior border which articulates with the frontal bone. 
5. The posterior border, which articulates with the ethmoid bone. 6. The anterior 
border, which articulates with the superior maxillary bone. 7. The border which arti- 
culates with the inferior turbinated bone. 

7* ' i 




78 PALATE BONES. 

concave, partly smooth and partly rough; smooth where it forms part of 
the temporal fossa, and rough where it articulates with the superior maxil- 
lary bone. 

The frontal process ascends perpendicularly to form the outer border 
of the orbit, and to articulate with the external angular process of the 
frontal bone. The orbital process is a thick plate, which projects inwards 
from the frontal process, and unites with the great ala of the sphenoid to 
constitute the outer wall of the orbit. It is pierced by several small fora- 
mina, for the passage of the temporo-malar filaments of the superior 
maxillary nerve. The maxillary process is broad, and articulates with 
the superior maxillary bone. The zygomatic process, narrower than the 
rest, projects backwards to unite with the zygoma of the temporal bone. 

Development. — By a single centre ; in rare instances, by two or three. 
In many animals the malar bone is permanently divided into two portions, 
orbital and malar. Ossification commences in the malar bone soon after 
the vertebrae. 

Articulations. — With four bones: three of the cranium, frontal, tem- 
poral) and sphenoid ; and one of the face, the superior maxillary bone. 

Attachment of Muscles. — To five : levator labii superioris proprius, 
zygomaticus minor and major, masseter, and temporal. 

Palate Bones. — The palate bones are situated at the posterior part of 
the nares, where they enter into the formation of the palate, the side of the 
, nose, and the posterior part of the floor of the orbit ; 

hence they might, with great propriety, be named the 
palato-naso-orbital bones. Each bone resembles, in 
general form, the letter L, and is divisible into a 
horizontal plate, a perpendicular plate, and a ptery- 
goid process or tuberosity. 

The horizontal plate is quadrilateral ; and presents 
two surfaces, one superior, which enters into the for- 
mation of the floor of the nares, the other inferior, 
forming the posterior part of the hard palate. The 
superior surface is concave, and rises towards the 
middle line, where it unites with its fellow of the 
opposite side and forms part of a crest (crista nasalis), which articulates 
with the vomer. The inferior surface is uneven, and marked by a slight 
transverse ridge, to which is attached the tendinous expansion of the ten- 
sor palati muscle. Near its external border are two openings, one large 
and one small, the posterior palatine foramina ; the former transmits the 

*A posterior view of the right palate bone in its natural position; it is slightly turned 
on one side, to obtain a sight of the internal surface of the perpendicular plate & (2). 1. The 
horizontal plate of the bone; its upper or nasal surface. 2. The perpendicular plate; 
its internal or nasal surface. 3, 10, 11. The pterygoid process or tuberosity 4 The 
thick internal border of the horizontal plate, which, articulating with the similar border 
of the opposite bone, forms the crista nasalis for the reception of the vomer 5 The 
pointed process, which, with a similar process of the opposite bone, forms the palate 
spine. G. The horizontal ridge which gives attachment to the inferior turbinated bone • 
the concavity below this ridge enters into the formation of the inferior meatus and the 
concavity (2) above the ridge into that of the middle meatus. 7. The spheno palatine 
notch. 8. The orbital portion. 9. The crista turbinalis superior for the middle turbi- 
nated bone. 10. The middle facet of the tuberosity, which enters into the formation of 
the pterygoid fossa. The facets 11 and 3 articulate with the two pterygoid phtes 11 
with the internal, and 3 with the external. ' 




PALATE BONES. 79 

posterior palatine nerve and artery, and the latter the middle palatine 
nerve. The posterior border is concave, and presents at its inner extre- 
mity a sharp point, which, with a corresponding point in the opposite 
bone, constitutes the palate spine for the attachment of the azygos uvulae 
muscle. 

The perpendicular plate is also quadrilateral ; and presents two surfaces, 
one internal or nasal, forming a part of the wall of the nares ; the other 
external, bounding the spheno-maxillary fossa and antrum. The internal 
surface is marked near its middle by a horizontal ridge (crista turbinalis 
inferior), to which is united the inferior turbinated bone ; and, at about 
half an inch above this is another ridge (crista turbinalis superior) for the 
attachment of the middle turbinated bone. The concave surface below 
the inferior ridge is the lateral boundary of the inferior meatus of the nose ; 
that between the two ridges corresponds with the middle meatus, and the 
surface above the superior ridge with the superior meatus. The external 
surface, extremely irregular, is rough on each side for articulation with 
neighbouring bones, and smooth in the middle to constitute the inner 
boundary of the spheno-maxillary fossa. This smooth surface terminates 
inferiorly in a deep groove, which being completed by the tuberosity of 
the superior maxillary bone and pterygoid process of the sphenoid, forms 
the posterior palatine canal. 

Near the upper part of the perpendicular plate is a large oval notch 
completed by the sphenoid, the spheno-palatine foramen, which transmits 
the spheno-palatine nerves and artery, and serves to divide the upper ex- 
tremity of the bone into two portions, an anterior or orbital, and a poste- 
rior or sphenoidal portion. The orbital portion is hollow within, and pre- 
sents five surfaces externally, three articular, and two free ; the three 
articular are the anterior, which looks forward and articulates with the 
superior maxillary bone, the internal with the eth- Flg . o 7 * 

moid, and the posterior with the sphenoid. The 
free surfaces are the superior or orbital, which forms 
the posterior part of the floor of the orbit, and the 
external, which looks into the spheno-maxillary fossa. 

The sphenoidal portion, much smaller than the 
orbital, has three surfaces, two lateral and one supe- 
rior. The external lateral surface enters into the 
formation of the spheno-maxillary fossa; the internal- 
lateral forms part of the lateral boundary of the nares ; 
and the superior surface articulates with the under 
part of the body of the sphenoid bone, and assists 
the sphenoidal spongy bones in closing the sphenoidal sinuses. This 
portion takes part in the formation of the pterygo-palatine canal. 
, The. pterygoid process or tuberosity of the palate bone is the thick and 
rough process which stands backwards from the angle of union of the 

The perpendicular plate of the palate bone seen upon its external or spheno-max- 
illary surface. 1. The rough surface of this plate, which articulates with the superior 
maxillary bone and bounds the antrum. 2. The posterior palatine canal, completed 
by the tuberosity of the superior maxillary bone and pterygoid process. The rough 
surface to the left of the canal (2) articulates with the internal pterygoid plate. 3. 
The spheno-palatine notch. 4, 5, 6. The orbital portion of the perpendicular plate. 4. 
The spheno-maxillary facet of this portion; 5, its orbital facet; 6, its maxillary facet, 
to articulate with the superior maxillary bone. 7. The sphenoidal portion of the per- 
pendicular plate. 8. The pterygoid process or tuberosity of the bone. 




80 INFERIOR TURBINATED BONES VOMER. 

horizontal with the perpendicular portion of the bone. It is received into 
the angular fissure, which exists between the two plates of the pterygoid 
process at their inferior extremity, and presents three surfaces : one con- 
cave and smooth, which forms part of the pterygoid fossa; and one at 
each side to articulate with the pterygoid plates. The anterior face of 
this process is rough, and articulates with the superior maxillary bone. 

Development. — By a single centre, which appears in the angle of union 
between the horizontal and perpendicular portion, at the same time with 
ossification in the vertebrae. 

Articulations. — With six bones : two of the cranium, the sphenoid and 
ethmoid ; and four of the face, the superior maxillary, inferior turbinated 
bone, vomer, and the palate bone of the opposite side. 

Attachment of muscles. — To four : the tensor palati, azygos uvula?, 
internal and external pterygoid. 

Inferior turbinated Bones. — The inferior turbinated or spongy bone, 
is a thin layer of light and porous bone, attached to the crista turbinalis 
inferior of the inner wall of the nares, and projecting inwards towards 
the septum narium. The inferior turbinated bone is broad in front, nar- 
row and tapering behind^ and slightly curled upon itself, so as to bear 
some resemblance to one valve of a bivalve shell, hence its designation 
concha inferior. The bone presents for examination a contex and a con- 
cave surface, and a superior and an inferior border. The convex surface 
looks inwards and upwards, and forms the inferior boundary of the middle 
meatus naris ; it is marked by several longitudinal grooves for branches 
of the spheno-palatine nerve and artery. The concave surface looks down- 
wards and outwards, and constitutes the roof of the inferior meatus. The 
superior border is irregular ; it is attached to the crista turbinalis inferior 
of the superior maxillary bone in front, to the same crest on the palate 
bone behind, and between those attachments gives off two, and sometimes 
three, thin and laminated processes. The most anterior of these processes, 
processus lachrymalis, articulates with the lachrymal bone, and assists in 
completing the nasal duct. The middle process, processus maxillaris, 
descends and assists in closing the antrum maxillare ; while the posterior, 
processus ethmoidalis, which is often wanting, ascends towards the eth- 
moid bone, and also takes part in the closure of the antrum maxillare. 
The inferior border is rounded, and thicker than the rest of the bone. 

Development. — By a single centre, which appears at about the middle 
of the first year. 

It affords no attachment to muscles. 

Articulations. — With four bones : the ethmoid, superior maxillary, la- 
chrymal, and palate. 

Vomer. — The vomer is a thin, quadrilateral, plate of bone, forming the 
posterior and inferior part of the septum of the nares. 

The superior border is broad and expanded, to articulate, in the middle, 
with the under surface of the body of the sphenoid, and on each side with 
the processus vaginalis of the pterygoid process. The anterior part of this 
border is hollowed into a sheath for the reception of the rostrum of the 
sphenoid. The inferior border is thin and irregular, and is received into 
the grooved summit of the crista nasalis. The posterior border is sharp 
and tree, and forms the posterior division of the two nares. The anteiior 



INFERIOR MAXILLARY BONE. 81 

border is more or less deeply grooved for the reception of the central la- 
mella of the ethmoid and the cartilage of the septum. This groove is an 
indication of the early constitution of the bone of two lamellae, united at 
the inferior border. The vomer not unfrequently presents a convexity to 
one or the other side, generally, it is said, to the left. 

Development. — By a single centre, which makes its appearance at the 
same time with those of the vertebrae. Ossification begins from below and 
proceeds upwards. At birth, the vomer presents the form of a trough, in 
the concavity of which the cartilage of the septum nasi is placed ; it is this 
disposition which subsequently enables the bone to embrace the rostrum of 
the sphenoid. 

The vomer has no muscles attached to it. 

Articulations. — With six bones: the sphenoid, ethmoid, two superior 
maxillary, and two palate bones, and with the cartilage of the septum. 

Inferior Maxillary Bone. — The lower jaw is the arch of bone which 
contains the inferior teeth ; it is divisible into a horizontal portion or body, 
and a perpendicular portion, the ramus, at each side. 

Upon the external surface of the body of the bone, at the middle line, 
and extending from between the two first incisor teeth to the chin, is a 
slight ridge, crista mentalis, which indicates the point of conjunction of 
the lateral halves of the bone in the young subject, the symphysis. Im- 
mediately external to this ridge is a depression which gives origin to the 
depressor labii inferioris muscle ; and, corresponding with the root of the 
lateral incisor tooth, another depression, the incisive fossa, for the levator 
labii inferioris. Further outwards is an oblique opening, the mental fora- 
men, for the exit of the inferior dental nerve and artery ; and below this 
foramen is the commencement of an oblique ridge which runs upwards 
and outwards to the base of the coronoid process and gives attachment to 
the depressor anguli oris, platysma myoides, and buccinator muscle. Near 
the posterior part of this surface is a rough impression made by the mas- 
seter muscle ; and immediately in front of this impression, a groove may 
occasionally be seen for the facial artery. The projecting tuberosity at the 
posterior extremity of the lower jaw, at the point where the body and ramus 
meet, is the angle. 

Upon the internal surface of the body of the bone, at the symphysis, are 
two small pointed tubercles ; immediately beneath these, two other tuber- 
cles, less marked and pointed ; beneath them a ridge, and beneath the 
ridge two rough depressions of some size. These four points give attach- 
ment, from above downwards, to the genio-hyo-glossi, genio-hyoidei, part 
of the mylo-hyoidei, and to the digastric muscles. Running outwards 
into the body of the bone from the above ridge is a prominent line, the 
■mylo-hyoidean ridge, which gives attachment to the mylo-hyoideus muscle, 
and by its extremity to the pterygo-maxillary ligament and superior con- 
strictor muscle. ' Immediately above the ridge, and by the side of the 
symphysis, is a smooth concave surface, which corresponds with the sub- 
lingual gland; and below the ridge, and more externally, a deeper fossa 
for the submaxillary gland. 

The superior border of the body of the bone is the alveolar process, 
furnished in the adult with alveoli for sixteen teeth. The inferior border 
or base is rounded and smooth; thick and everted in front to form the 
chin, and thin behind where it merges into the angle of the bone. 

F 




82 INFERIOR MAXILLARY BONE. 

The ramus is a strong square-shaped process, differing in direction at 
various periods of life ; thus, in the foetus and infant, it is almost parallel 
With the body ; in youth it is oblique, and it gradually approaches the ver- 
tical direction until manhood ; in old age, after the loss of the teeth, it 
again declines and assumes the oblique direction. Upon its external sur- 
face it is rough, for the attachment of the masseter muscle ; and at the 
junction of its posterior border with the body of the bone is a rough tuber- 
osity, the angle of the lower jaw, which gives attachment by its inner 
margin to the stylo-maxillary ligament. 

■p. 3g * The upper extremity of the ramus pre- 

sents two processes, separated by a con- 
cave sw r eep, the sigmoid notch. The an- 
terior is the coronoid process ; it is sharp 
and pointed, and gives attachment by its 
inner surface to the temporal muscle. 
The anterior border of the coronoid pro- 
cess is grooved at its lower part for the 
buccinator muscle. The posterior pro- 
cess is the condyle of the lower jaw, which 
is flattened from before backwards, oblique 
in direction, and smooth upon its upper 
surface, to articulate with the glenoid ca- 
vity of the temporal bone. The constriction around the base of the con- 
dyle is its neck, into which is inserted the external pterygoid muscle. The 
sigmoid notch is crossed by the masseteric artery and nerve. 

The internal surface of the ramus is marked near its centre by a large 
oblique foramen, the inferior dental, for the entrance of the inferior dental 
artery and nerve into the dental canal. Bounding this opening is a sharp 
margin, to which is attached the internal lateral ligament, and passing 
downwards from the opening a narrow groove which lodges the mylo- 
hyoidean nerve with a small artery and vein. To the uneven surface 
above, and in front of the inferior dental foramen, is attached the temporal 
muscle, and to that below it the internal pterygoid. The internal surface 
of the neck of the condyle gives attachment to the external pterygoid 
muscle ; and the angle to the stylo-maxillary ligament. 

Development. — By two centres : one for each lateral half, the two sides 
meeting at the symphysis, where they become united. The lower jaw is 
the earliest of the bones of the skeleton to exhibit ossification, with the 
exception of the clavicle ; ossific union of the symphysis takes place during 
the first year. 

Articulations. — "With the glenoid fossae of the two temporal bones, 
through the medium of a fibro -cartilage. 

Attachment of Muscles. — To fourteen pairs : by the external surface, 
commencing at the symphysis and proceeding outwards, — levator labii 
inferioris, depressor labii inferioris, depressor anguli oris, platysma myoides, 

* The lower jaw. 1. The body. 2. The ramus. 3. The symphysis. 4. The fossa 
for the depressor labii inferioris muscle. 5. The mental foramen. 6. The external 
oblique ridge. 7. The groove for the facial artery ; the situation of the groove is marked 
by a notch in the bone a little in front of the number. 8. The angle. 9. The extremity 
of the mylo-hyoidean ridge. 10. The coronoid process. 11. The condyle. 12. The 
sigmoid notch. 13. The inferior dental foramen. 14. The mylo-hyoidean groove. 15. 
The alveolar process, i. The middle and lateral incisor tooth of one side. i. The ca- 
nine tooth, b. The two bicuspides. m. The three molares. 



TABLE OF DEVELOPMENTS, ARTICULATIONS, ETC. 



83 



buccinator, and masseter; by the internal surface, also commencing at the 
symphysis, the genio-hyo-glossus, genio-hyoideus, mylo-hyoideus, digas- 
tricus, superior constrictor, temporal, external pterygoid, and internal 
pterygoid. 

Table showing the Points of Development, Articulations, and Attachment 
of Muscles, of the Bones of the Head. 



Development. 




, Articulations. 




Attachment of Muscles 


Occipital . , . 
Parietal .... 


7 
1 








. 6 . 
. 5 . 






. 13 pairs. 
1 muscle. 


Frontal . . . . 
Temporal . . . 
Sphenoid 
Ethmoid . . . 


2 
5 
12 . 
3 . 








. 12 . 
. 5 . 

12 . 

13 . 






2 pairs. 
14 muscles. 
12 pairs, 
none. 


Nasal .... 


1 


- 






4 . 






none. 


Superior maxillary 
Lachrymal . . . 
Malar .... 


4 








9 . 
4 . 
4 . 






9 muscles. 
1 ib. 
5 ib. 


Palate .... 










6 . . 






4 ib. 


Inferior turbinated 










4 . 






none. 


Vomer .... 










6 . 






none. 


Lower jaw . . . 


2 ' 








2 . 






14 pairs. 






SI 


JTl 


JR 


ES. 









The bones of the cranium and face are connected with each other by 
means of sutures (sutura, a seam), of which there are four principal varie- 
ties — serrated, squamous, harmonia, and schindylesis. 

The serrated suture is formed by the union of two borders possessing 
serrated edges, as in the coronal, sagittal, and lambdoid sutures. In these 
sutures the serrations are formed almost wholly by the external table, the 
edges of the internal table lying merely in apposition. 

The squamous suture (squama, a scale) is formed by the overlapping of 
the bevelled edges of two contiguous bones, as in the articulation between 
the temporal and the lower border of the parietal. In this suture the ap- 
proximated surfaces are roughened, so as to adhere mechanically with 
each other. 

The harmonia suture (afsiv, to adapt) is the simple apposition of conti- 
guous surfaces, the surfaces being more or less rough and retentive. This 
suture is seen in the connection between the superior maxillary bones, or 
of the palate processes of the palate bones with each other. 

The schindylesis suture [<rxiv$uki)4isj a fissure) is the reception of one bone 
into a sheath or fissure of another, as occurs in the articulation of the ros- 
trum of the sphenoid with the vomer, or of the latter with the perpendicular 
lamella of the ethmoid, and with the crista nasalis of the superior maxil- 
lary and palate bones. 

The serrated suture is formed by the interlocking of the radiating fibres 
along the edges of the flat bones of the cranium during growth. When 
this process is retarded in the infant by over-distension of the head, as in 
hydrocephalus, and sometimes without any such apparent cause, distinct 
ossific centres are developed in the interval between the edges; and, being 
surrounded by the suture, from independent pieces, which are called ossa 



84 SUPERIOR REGION OF THE SKULL. 

triquetra, or ossa Wormiana. In the lambdoid suture there is generally- 
one or more of these bones ; and in a beautiful adult hydrocephalic skele- 
ton, in the possession of Mr. Liston, there are upwards of one hundred. 

The coronal suture (fig. 39) extends transversely across the vertex of the 
skull, from the upper part of the greater wing of the sphenoid of one side 
to the same point on the opposite side ; it connects the frontal with the 
parietal bones. In the formation of this suture the edges of the articu- 
lating bones are bevelled, so that the parietal rest upon the frontal at each 
side, and in the middle the frontal rests upon the parietal bones ; they thus 
afford each other mutual support in the consolidation of the skull. 

The sagittal suture (fig. 39) extends longitudinally backwards along 
the vertex of the skull, from the middle of the coronal to the apex of the 
lambdoid suture. It is very much serrated, and serves to unite the two 
parietal bones. In the young subject, and sometimes in the adult, this 
suture is continued through the middle of the frontal bone to the root of 
the nose, under the name of the frontal suture. Ossa triquetra are some- 
times found in the sagittal suture. 

The lambdoid suture is named from some resemblance to the Greek 
letter A, consisting of two branches, which diverge at an acute angle from 
the extremity of the sagittal suture. This suture connects the occipital 
with the parietal bones. At the posterior and inferior angle of the parietal 
bones, the lambdoid suture is continued onwards in a curved direction into 
the base of the skull, and serves to unite the occipital bone with the mas- 
toid portion of the temporal, under the name of additamentum sutura 
lambdoidalis. It is in the lambdoid suture that ossa triquetra occur most 
frequently. 

The squamous suture (fig. 39) unites the squamous portion of the tem- 
poral bone with the greater ala of the sphenoid, and with the parietal, 
overlapping the lower border of the latter. The portion of the suture 
which is continued backwards from the squamous portion of the bone to 
the lambdoid suture, and connects the mastoid portion with the posterior 
inferior angle of the parietal, is the additamentum sutura squamosce. 

The additamentum suturae lambdoidalis, and additamentum sutune 
squamosa?, constitute together the mastoid suture. 

Across the upper part of the face is an irregular suture, the transverse, 
which connects the frontal bone with the nasal, superior maxillary, lachry- 
mal, ethmoid, sphenoid, and malar bones. The remaining sutures are 
too unimportant to deserve particular names or description. 

REGIONS OF THE SKULL. 

The skull, considered as a whole, is divisible into four regions: a supe- 
rior region, or vertex ; a lateral region; an inferior region, or base ; and 
an anterior region, the face. 

The superior region, or vertex of the skull, is bounded anteriorly by 
the frontal eminences ; on each side by the temporal ridges and parietal 
eminences ; and behind by the superior curved line of the occipital bone 
and occipital protuberance. It is crossed transversely by the coronal 
suture, and marked from before backwards by the sagittal, which termi- 
nates posteriorly in the lambdoid suture. Near the posterior extremity 
of the region, and on each side of the sagittal suture, is the parietal 
foramen. 



LATERAL REGION OF THE SKULL. 



85 



Upon the inner or cerebral surface of this region is a shallow groove, 
extending along the middle line from before backwards, for the superior 



Fig. 39 * 



Fig. 40.f 





longitudinal sinus ; on either side of this groove are several small fossae 
for the Pacchionian bodies, and further outwards, digital fossae correspond- 
ing with the convexities of the convolutions, and numerous ramified mark- 
ings for lodging the branches of the arteria meningea media. 

The lateral region of the skull is divisible into three portions ; tem- 
poral, mastoid, and zygomatic. 

The temporal portion, or temporal fossa, is bounded above and behind 
by the temporal ridge, in front by the external angular process of the 

* A front view of the skull. I. The frontal portion of the frontal bone. The 2, im- 
mediately over the root of the nose, refers to the nasal tuberosity; the 3. over the orbit, 
to the supra-orbital ridge. 4. The optic foramen. 5. The sphenoidal fissure. 6. The 
spheno-maxillary fissure. 7. The lachrymal fossa in the lachrymal bone, the com- 
mencement of the nasal duct. The figures 4, 5, 6, 7, are within the orbit. 8. The 
opening of the anterior nares, divided into two parts by the vomer; the number is 
placed upon the latter. 9. The infra-orbital foramen. 10. The malar bone. 11. The 
symphisis of the lower jaw. 12. The mental foramen. 13. The ramus of the lower 
jaw. 14. The parietal bone. 15. The coronal suture. 16. The temporal bone. 17. 
The squamous suture. 18. The upper part of the great ala of the sphenoid bone. 19. 
The commencement of the temporal ridge. 20. The zygoma of the temporal bone, 
assisting to form the zygomatic arch. 21. The mastoid process. 

fThe cerebral surface of the base of the skull. 1. One side of the anterior fossa; the 
number is placed on the roof of the orbit, formed by the orbital plate of the frontal bone. 
2. The lesser wing of the sphenoid. 3. The crista galli. 4. The foramen caecum. 
5. The cribriform lamella of the ethmoid. 6. The processus olivaris. 7. The foramen 
npticum. 8. The anterior clinoid process. 9. The carotid groove upon the side of the 
sella turcica, for the internal carotid artery and cavernous sinus. 10, 11, 12. The 
middle fossa of the base of the skull. 10. Marks the great ala of the sphenoid. 11. 
The squamous portion of the temporal bone. 12. The petrous portion of the temporal. 
13. The sella turcica. 14. The basilar portion of the sphenoid and occipital bone 
(clivus Blumenbachii). The uneven ridge between Nos. 13, 14, is the dorsum ephippii, 
and the prominent angles of this ridge the posterior clinoid processes. 15. The fora- 
men rotundum. 16. The foramen ovale. 17. The foramen spinosum ; the small irre- 
gular opening between 17 and 12 is the hiatus Fallopii. 18. The posterior fossa of the 
base of the skull. 19, 19. The groove for the lateral sinus. 20. The ridge upon the 
occipital bone, which gives attachment to the falx cerebelli. 21. The foramen magnum, 
22. The meatus auditorius internus. 23. The jugular foramen. 

8 



86 BASE OF THE SKULL. 

frontal bone and by the malar bone, and below by the zygoma. It is 
formed by part of the frontal, great wing of the sphenoid, parietal, squa- 
mous portion of the temporal, malar bone, and zygoma, and lodges the 
temporal muscle with the deep temporal arteries and nerves. 

The mastoid portion is rough, for the attachment of muscles. Upon its 
posterior part is the mastoid foramen, and below, the mastoid process. 
In front of the mastoid process is the external auditory foramen, surrounded 
by the external auditory process ; and in front of this foramen the glenoid 
cavity, bounded above by the middle root of the zygoma and in front by. 
its tubercle. 

The zygomatic portion or fossa is the irregular cavity below the zygoma, 
bounded in front by the superior maxillary bone, internally by the exter- 
nal pterygoid plate, above by part of the great wing of the sphenoid and 
squamous portion of the temporal bone, and by the temporal fossa, and 
externally by the zygomatic arch and ramus of the lower jaw. It con- 
tains the external pterygoid, with part of the temporal and internal ptery- 
goid muscle, and the internal maxillary artery and inferior maxillary nerve, 
with their branches. On the inner and upper side of the zygomatic fossa 
are two fissures, the spheno-maxillary and the pterygo-maxillary. The 
spheno-maxillary fissure is horizontal in direction, opens into the orbit, 
and is situated between the great ala of the sphenoid and the superior 
maxillary bone. It is completed externally by the malar bone. The 
pterygo-maxillary fissure is vertical," and descends at right angles from the 
extremity of the preceding. It is situated between the pterygoid process 
and the tuberosity of the superior maxillary bone, and transmits the inter- 
nal maxillary artery. At the angle of junction of these two fissures is a 
small space, the spheno-maxillary fossa, bounded by the sphenoid, palate, 
and superior maxillary bone. In this space are seen the openings of five 
foramina, — the foramen rotundum, spheno-palatine, pterygopalatine, pos- 
terior palatine, and Vidian. The spheno-maxillary fossa lodges Meckel's 
ganglion and the termination of the internal maxillary artery. 

The base of the skull presents an internal or cerebral, and an exter- 
nal or basilar surface. 

The cerebral surface is divisible into three parts, which are named the 
anterior, middle, and posterior fossa of the base of the cranium. The 
anterior fossa is somewhat convex on each side, where it corresponds with 
the roofs of the orbits ; and concave in the middle, in the situation of the 
ethmoid bone and the anterior part of the body of the sphenoid. The 
latter and the lesser wings constitute its posterior boundary. It supports 
the anterior lobes of the cerebrum. In the middle line of this fossa, at its 
anterior part, is the crista galli ; immediately in front of this process, the 
foramen cacum; and on each side the cribriform plate, with its foramina, 
for the transmission of the filaments of the olfactory and nasal branch of 
the opthalraic nerve. Farther back in the middle line is the processus 
olivaiis, and on the sides of this process the optic foramina, anterior and 
middle clinoid processes, and vertical grooves for the internal carotid 
arteries. 

The middle fossa of the base, deeper than the preceding, is bounded in 
front by the lesser wing of the sphenoid ; behind, by the petrous portion 
of the temporal bone ; and is divided into two lateral parts by the sella 
turcica. It is formed by the posterior part of the body, great ala and 
spinous process of the sphenoid, and bv the petrous and squamous portion 



BASE OF THE SKULL. 



87 



of the temporal bones. In the centre of this fossa is the sella turcica, 
which lodges the pituitary gland, bounded in front by the anterior and 
middle, and behind by the posterior clinoid processes. On each side of the 
sella turcica is the carotid groove for the internal carotid artery, the 
cavernous plexus of nerves, the cavernous sinus, and the orbital nerves ; 
and a little farther outwards the following foramina, from before back- 
wards : — sphenoidal Jis sure (foramen lacerum anterius), for the transmission 
of the third, fourth, three branches of the ophthalmic division of the fifth, 
and the sixth nerve, and ophthalmic vein ; foramen rotundum, for the 
superior maxillary nerve ; foramen ovale, for the inferior maxillary nerve> 
arteria meningea parva, and nervus petrosus superficialis minor ; foramen 
spinosum, for the arteria meningea media ; foramen lacerum basis cranii, 
which gives passage to the internal carotid artery, carotid plexus, and 
petrosal branch of the Vidian nerve. On the anterior surface of the 
petrous portion of the temporal bone is a groove, leading to a fissured 
opening, the hiatus Fallopii, for the petrosal branch of the Vidian nerve ; 
and, immediately beneath this, a smaller foramen, for the nervus petrosus 
superficialis minor. Towards the apex of the petrous portion is the notch 
for the fifth nerve, and below it a slight depression for the Casserian gan- 
glion. Farther outwards is the eminence which marks the position of the 
perpendicular semicircular canal. Proceeding from the foramen spinosum, 
are two grooves which indicate the course of the trunks of the arteria 
meningea media. The whole fossa lodges the middle lobes of the 
cerebrum. 

The posterior fossa, larger than the other two, is formed by the occipital 
bone, by the petrous and mastoid portion of the temporals, and by a small 
part of the sphenoid and parietals. It is 
bounded in front by the upper border 
of the petrous portion and dorsum ephip- 
pii, and along its posterior circumference 
by the groove for the lateral sinuses ; it 
gives support to the pons Varolii, medulla 
oblongata, and cerebellum. In the centre 
of this fossa is the foramen magnum, 
bounded on each side by a rough tuber- 
cle, which gives attachment to the odon- 
toid ligament, and by the anterior condy- 
loid foramen. In front of the foramen 
magnum is the concave surface (clivus 
Blumenbachii) which supports the me- 
dulla oblongata and pons Varolii, and on 
each side the following foramina, from 
before backwards : — the internal auditory 
foramen, for the auditory and facial nerve 
and auditory artery ; behind, and exter- 
nally to this, is a small foramen leading 

*The external or basilar surface of the base of the skull. 1, 1. The hard palate. 
The figures are placed upon the palate processes of the superior maxillary bones. 
2. The incisive, or anterior palatine foramen. 3. The palate process of the palate bone. 
The large opening near the figure is the posterior palatine foramen. 4. The palate 
spine ; the curved line upon which the number rests is the transverse ridge. 5. The 
vomer, dividing the openings of the posterior nares. 6. The iuternal pterygoid plate. 



Fig. 41* 




88 BASE OF THE SKULL. 

into the aqaceductus vestibuli ; and below it, partly concealed by the edge 
of the petrous bone, the aquceductus cochleae; next, a long fissure, the 
foramen lacerum postenus, or jugular foramen, giving passage externally 
to the commencement of the internal jugular vein, and internally to the 
eighth pair of nerves. Converging towards this foramen from behind is 
the deep groove for the lateral sinus, and from the front the groove for the 
inferior petrosal sinus. 

Behind the foramen magnum is a longitudinal ridge, which gives at- 
tachment to the falx cerebelli, and divides the two inferior fossae of the 
occipital bone ; and above the ridge is the internal occipital protuberance 
and the transverse groove lodging the lateral sinus. 

The external surface of the base of the skull is extremely irregular. 
From before backwards it is formed by the palate processes of the superior 
maxillary and palate bones ; the vomer ; pterygoid, spinous processes, and 
part of the body of the sphenoid ; under surface of the squamous, petrous, 
and mastoid portion of the temporals ; and by the occipital bone. The 
palate processes of the superior maxillary and palate bones constitute the 
hard palate, which is raised above the level of the rest of the base, and is 
surrounded by the alveolar processes containing the teeth of the upper 
jaw. At the anterior extremity of the hard palate, and directly behind 
the front incisor teeth, is the anterior palatine or incisive foramen, the ter- 
mination of the anterior palatine canal, which contains the naso-palatine 
ganglion, and transmits the anterior palatine nerves. At the posterior 
angles of the palate are the posterior palatine foramina, for the posterior 
palatine nerves and arteries. Passing inwards from these foramina are the 
transverse ridges to which are attached the aponeurotic expansions of the 
tensor palati muscles ; and at the middle line of the posterior border, the 
palate spine, which gives origin to the azygos uvulae. The hard palate 
is marked by a crucial suture, which distinguishes the four processes of 
which it is composed. Behind, and above the hard palate, are the poste- 
rior nares, separated by the vomer, and bounded on each side by the pte- 
rygoid processes. At the base of the pterygoid processes are the pterygo- 
palatine 'canals. The internal pterygoid plate is long and narrow, termi- 
nated at its apex by the hamular process, and at its base by the scaphoid 
fossa. The external plate is broad ; the space between the two is the 
pterygoid fossa ; it contains part of the internal pterygoid muscle, and the 
tensor palati. Externally to the external pterygoid plate is the zygomatic 
fossa. Behind the nasal fossa?, in the middle line, is the under surface of 
the body of the sphenoid, and the basilar process of the occipital bone, 
and, still further back, the foramen magnum. At the base of the external 
pterygoid plate, on each side, is the foramen ovale, and behind this the 
foramen spinosum with the prominent spine which gives attachment to the 
internal lateral ligament of the lower jaw and the laxator tympani muscle. 
Running outwards from the apex of the spinous process of the sphenoid 

7. The scaphoid fossa. 8. The external pterygoid plate. The interval between 6 and 
8 (right side of the figure) is the pterygoid fossa. 9. The zygomatic fossa. 10. The 
basilar process of the occipital bone. 11. The foramen magnum. 12. The foramen 
ovale. 13. The foramen spinosum. 14. The glenoid fossa. 15. The meatus audito- 
rius externus. 16. The foramen lacerum anterius basis cranii. 17. The carotid fora- 
men of the left side. 18. The foramen lacerum posterius, or jugular foramen. 19. The 
styloid process. 20. The stylo-mastoid foramen. 21. The mastoid process. 22. One 
of the condyles of the occipital bone. 23. The posterior condyloid fossa. 



REGION OF THE FACE. 89 

bone, is the fissura Glaseri, which crosses the glenoid fossa transversely, 
and divides it into an anterior smooth surface, bounded by the eminentia 
articularis, for the condyle of the lower jaw, and a posterior rough surface 
for a part of the parotid gland. Behind the foramen ovale and spinosum, 
is the irregular fissure between the spinous process of the sphenoid bone 
and the petrous portion of the temporal, the foramen lacerum anterius basis 
cranii, which lodges the internal carotid artery and Eustachian tube, and in 
which the carotid branch of the Vidian nerve joins the carotid plexus. 
Following the direction of this fissure outwards we see the foramen for the 
Eustachian tube, and that for the tensor tympani muscle, separated from 
each other by the processus cochleariformis. Behind the fissure is the 
pointed process of the petrous bone which gives origin to the levator pa- 
lati muscle, and, externally to this process, the carotid foramen for the 
transmission of the internal carotid artery and the ascending branch of the 
superior cervical ganglion of the sympathetic ; and behind the carotid 
foramen, the foramen lacerum posterius and jugular fossa. Externally, 
and somewhat in front of the latter, is the styloid process, and at its base 
the vaginal process. Behind and at the root of the styloid process is the 
stylo-mastoid foramen, for the facial nerve and stylo-mastoid artery, and 
further outwards the mastoid process. Upon the inner side of the root 
of the mastoid process is the digastric fossa ; and a little farther inwards, 
the occipital groove. On either side of the foramen magnum, and near 
its anterior circumference, are the condyles of the occipital bone. In 
front of each condyle, and piercing its base, is the anterior condyloid fora- 
men for the hypoglossal nerve, and directly behind the condyle the irre- 
gular fossa in which the posterior condyloid foramen is situated. Behind 
the foramen magnum are the two curved lines of the occipital bone, the 
spine, and the protuberance, with rough surfaces for the attachment of 
muscles. 

The Face is somewhat oval in contour, uneven in surface, and exca- 
vated for the reception of two principal organs of sense, — the eye and the 
nose. It is formed by part of the frontal bone and by the bones of the 
face. Superiorly it is bounded by the frontal eminences ; beneath these 
are the superciliary ridges, converging towards the nasal tuberosity; be- 
neath the superciliary ridges are the supra-orbital ridges, terminating ex- 
ternally in the external border of the orbit, and internally in the internal 
border, and presenting towards their inner third the supra-orbital notch, 
for the supra-orbital nerve and artery. Beneath the supra-orbital ridges 
are the openings of the orbits. Between the orbits is the bridge of the 
nose, over-arching the anterior nares ; and on each side of this opening 
the canine fossa of the superior maxillary bone, the infra-orbital foramen, 
and still farther outwards the prominence of the malar bone ; at the lower 
margin of the anterior nares is the nasal spine, and beneath this the supe- 
rior alveolar arch, containing the teeth of the upper jaw. Forming the 
lower boundary of the face is the lower jaw, containing in its alveolar 
process the lower teeth, and projecting inferiorly to form the chin; on 
either side of the chin is the mental foramen. If a perpendicular line be 
drawn from the inner third of the supra-orbital ridge to the inner third of 
the body of the lower jaw, it will be found to intersect three openings ; — 
the supra-orbital, infra-orbital, and mental, each giving passage to a facial 
branch of the fifth nerve. 
8* 



90 ORBITS — NASAL FOSSAE. 



ORBITS. 



The orbits are two quadrilateral hollow cones, situated in the upper 
part of the face, and intended for the reception of the eye-balls, with their 
muscles, vessels, and nerves, and the lachrymal glands. The central axis 
of each orbit is directed outwards, so that the axis of the two, continued 
into the skull through the optic foramina, would intersect over the middle 
of the sella turcica. The superior boundary of the orbit is formed by the 
orbital plate of the frontal bone, and by part of the lesser wing of the 
sphenoid ; the inferior, by part of the malar bone and by the orbital pro- 
cesses of the superior maxillary and palate bone ; the internal, by the 
lachrymal bone, the os planum of the ethmoid, and part of the body of the 
sphenoid ; and the external, by the orbital process of the malar bone and 
the great ala of the sphenoid. These may be expressed more clearly in a 
tabular form : — 

Frontal. 
Sphenoid (lesser wing). 

Inner wall. QuUr wall 

Lachrymal. Orbit. Malar. 

Ethmoid ("os planum). e^k-««.:J y„^«„*«. ,..:„„\ 

Sphenoid (body). S P hen0ld ( greater Wing ^ 

| ; 

Malar. 

Superior Maxillary. 

Palate. 

There are nine openings communicating with the orbit : the optic, for 
the admission of the optic nerve and ophthalmic artery ; the sphenoidal 
fissure, for the transmission of the third, fourth, the three branches of the 
ophthalmic division of the fifth nerve, the sixth nerve, and the ophthalmic 
vein ; the spheno-maxillary fissure, for the passage of the superior maxil- 
lary nerve and artery to the opening of entrance of the infra-orbital canal ; 
temporo-malar foramina — two or three small openings in the orbital pro- 
cess of the malar bone, for the passage of filaments of the orbital branch 
of the superior maxillary nerve ; anterior and posterior ethmoidal foramina 
in the suture between the os planum and frontal bone, the former trans- 
mitting the nasal nerve and anterior ethmoidal artery, the latter the poste- 
rior ethmoidal artery and vein ; the opening of the nasal duct; and the 
supra-orbital notch or foramen, for the supra-orbital nerve and artery. 

NASAL FOSSJl. 

The nasal fossae are two irregular cavities, situated in the middle of the 
face, and extending from before backwards. They are bounded above by 
the nasal bones, ethmoid, and sphenoid : below by the palate processes of 
the superior maxillary and palate bones; externally by the superior maxil- 
lary, lachrymal, inferior turbinated, superior and middle turbinated bones 
of the ethmoid, palate, and internal pterygoid plate of the sphenoid ; and 
the two fossae are separated by the vomer and the perpendicular lamella 
of the ethmoid. These may be more clearly expressed in a tabular 
form : — 



NASAL FOSSiE. 



91 



Nasal bones. 
Ethmoid. 
Sphenoid. 



a 


T3 X 


ex. 


2 s 


T3 


d _; S 


o . 


-o* .9 « "S 


be a) 


' 3 -s Is 


bS 


S et 


J ** J3 M 


o,eu 


Et 

rior 
Lac 
erio 


c 


« a« 


>- 


S 3 


e 


M GO 




Nasal fossa. 



>* FT) — « 

— _• m tJ 

"S g .S T3 ■ '3 

n « .2 W - 



oj i—l . 



Fig. 42/ 




Palate processes of superior maxillary. 
Palate processes of palate bone. 

E^h nasal fossa is divided into three irregular longitudinal passages, 
or mtatuses, by three processes of bone, which project from its outer wall, 
the superior, middle, and inferior turbi- 
nated bones; the superior and middle 
turbinated bones being processes of the 
ethmoid, and the inferior a distinct bone 
of the face. The superior meatus occu- 
pies the superior and posterior part of 
each fossa ; it is situated between the 
superior and middle turbinated bones, 
and has opening into it three foramina, 
viz. the opening of the posterior ethmoid 
cells, the opening of the sphenoid cells, 
and the spheno-palatine foramen. The 
middle meatus is the space between the 
middle and inferior turbinated bones; 
it also presents three foramina, the open- 

* A longitudinal section of the nasal fossae made immediately to the right of the 
middle line, and the bony septum removed in order to show the external wall of the 
left fossa. 1. The frontal bone. 2. The nasal bone. 3. The crista galli process of the 
ethmoid. The groove between 1 and 3 is the lateral boundary of the foramen caecum. 
4. The cribriform plate of the ethmoid. 5. Part of the sphenoidal cells. 6. The basilar 
portion of the sphenoid bone. Bones 2, 4, and 5, form the superior boundary of the 
nasal fossa. 7, 7. The articulating surface of the palatine process of the superior maxil- 
lary bone. The groove between 7, 7, is the lateral half of the incisive canal, and the 
dark aperture in the groove the inferior termination of the left naso-palatine canal 
8. The nasal spine. 9. The palatine process of the palate bone. a. The superior tur- 
binated bone, marked by grooves and apertures for filaments of the olfactory nerve. 
6. The superior meatus, c. A probe passed into the posterior ethmoidal cells, d. The 
opening of the sphenoidal cells into the superior meatus, e. The spheno-palatine fora- 
men. /. The middle turbinated bone, g, g. The middle meatus, h. A probe passed 
into the infundibular canal, leading from the frontal sinuses and anterior ethmoid cells; 
the triangular aperture immediately above the letter is the opening of the maxillary 
sinus i. The inferior turbinated bone, k, k. The inferior meatus. £, I. A probe passed 
up the nasal duct, showing the direction of that canal. The anterior letters g, k, are 
placed on the superior maxillary bone, the posterior on the palate bone. m. The in- 
ternal pterygoid plate, n. Its hamular process, o. The external pterygoid plate, p. The 
situation of the opening of the Eustachian tube. q. The posterior palatine foramina, 
r. The roof of the left orbit, s. The optic foramen, t. The groove for the last turn of 
the internal carotid artery converted into a foramen by the development of an osseous 
communication between the anterior and middle clinoid processes, v. The sella turcica. 
z. The posterior clinoid process. 



92 



TEETH CLASSIFICATION. 



ing of the frontal sinuses, of the anterior ethmoid cells, and of the antrum. 
The largest of the three passages is the inferior meatus, which is the space 
between the inferior turbinated bone and the floor of the fossa ; in it there 
are two foramina, the termination of the nasal duct, and one opening of 
the anterior palatine canal. The nasal fossae commence upon the face by 
a large irregular opening, the anterior nares, and terminate posteriorly in 
the two posterior nares. 



TEETH. 



Man is provided with two successions of teeth ; the first are the teeth 
of childhood, they are called temporary, deciduous, or milk teeth ; the 
second continue until old age, and are named permanent. 




/ e h 

The permanent teeth are thirty-two in number, sixteen in each jaw ; they 
are divisible into four classes, — incisors, of which there are four in each 
jaw, two central and two lateral ; canine, tw r o above and two below ; 
bicuspid, four above and four below; and molars, six above and six 
below. 

The temporary teeth are twenty in number (fig. 44) ; eight incisors, 
four canine, and eight molars. The temporary molars have four tubercles, 
and are succeeded by the permanent bicuspides, which have only two 
tubercles. 

Each tooth is divisible into a crown, which is the part apparent above 
the gum ; a constricted portion around the base of the crown, the neck, 
and a root or fang, which is contained within the alveolus. The root is 
invested by periosteum, which lines the alveolus, and is then reflected 
upon the root of the tooth as far as its neck. 

The incisor teeth (cutting teeth) are named from presenting a sharp and 
cutting edge, formed at the expense of the posterior surface. The crown 
is flattened from before backwards, being somewhat convex in front and 
concave behind ; the neck is considerably constricted, and the root com- 
pressed from side to side ; at its apex is a small opening for the passage 
of the nerve and artery of the tooth. 

•Permanent teeth. n . Central incisor, b. Lateral incisor, c. Cuspid or canine 
d. rirst bicuspid, e. Second bicuspid. /. First molar, g. Second molar, h Third 
molar or dens sapientiee. 



STRUCTURE OF TEETH. 

Fig. 44.* 



93 




The canine teeth (cuspidati) follow the incisors in order from before 
backwards ; two are situated in the upper jaw, one on each side, and two 
in the lower. The crown is larger than that of the incisors, convex be- 
fore and concave behind, and tapering to a blunted point. The root is 
longer than that of all the other teeth, compressed at each side, and 
marked by a slight groove. 

The bicuspid teeth (bicuspidati, small molars), two on each side in each 
jaw, follow the canine, and are intermediate in size between them and 
the molars. The crown is compressed from before backwards, and sur- 
mounted by two tubercles, one internal, the other external ; the neck is 
oval : the root compressed, marked on each side by a deep groove, and 
bifid near its apex. The teeth of the upper jaw have a greater tendency 
to the division of their roots than those of the lower, and the posterior 
than the anterior pair. 

The molar teeth (multicuspidati, grinders), three on each side in each 
jaw, are the largest of the permanent set. The crown is quadrilateral, 
and surmounted by four tubercles, the neck large and round, and the root 
divided into several fangs. In the upper jaw the first and second molar 
teeth have three roots, sometimes four, which are more or less widely 
separated from each other, two of the roots being external, the other in- 
ternal. In the lower there are but two roots, which are anterior and pos- 
terior ; they are flattened from behind forwards, and grooved so as to 
mark a tendency to division. The third molars, or dentes sapientise, are 
smaller than the other two ; they present three tubercles on the surface of 
the crown ; and the root is single and grooved, appearing to be made up 
of four or five fangs compressed together, or partially divided. In the 
lower jaw the fangs are frequently separated to some distance from each 
other, and much curved, so as to offer considerable resistance in the ope- 
ration of extraction.! 

Structure. — The base of the crown of each tooth is hollowed in its in- 
terior into a small cavity which is continuous with a canal passing through 
the middle of each fang. The cavity and canal, or canals, constitute the 
cavitas pulpce, and contain a soft cellulo-vascular organ, the pulp, which 
receives its supply of vessels and nerves through the small opening at the 
apex of each root. Mr. Nasmyth, to whose investigations science is so 

* Temporary teeth, a. Central incisor, b. Lateral incisor, c. Canine, d. First mo- 
lar, e. Second molar. 

f See an excellent practical work, " On the Structure, Economy, and Pathology of the 
Teeth," by Mr. Lintott. 



94 



STRUCTURE OF TEETH. 



Fig. 45 * 



much indebted for our present knowledge of the intimate structure and 
development of the teeth, has observed with regard to the pulp, that it is 
composed of two different tissues, vascular and reticular ; the former 
being an intricate web of minute vessels terminating in simple capillary 
loops, the latter a network of nucleated cells in which calcareous salts are 
gradually deposited, and which by a systematic continuance of that pro- 
cess are gradually converted into ivory. This process naturally takes 
place at the surface of the pulp, and as the pulp is thus robbed of its cells, 
new cells are produced by the capillary plexus to supply their place, and 
be in their turn similarly transformed. 

A tooth is composed of three distinct structures, ivory or tooth-bone 
enamel, and a cortical substance or cementum. 
The ivory consists of very minute, tapering, and 
branching fibres embedded in a dense homogene- 
ous, interfibrous substance. The fibres commence 
by their larger ends at the walls of the cavitas 
pulpae and pursue a radiating and serpentine course 
towards the periphery of the tooth, where they ter- 
minate in ramifications of extreme minuteness. 
These fibres, heretofore considered to be hollow 
tubuli, have been shown by Mr. Nasrnyth to be 
rows of minute opaque bodies, arranged in a linear 
series (baccated fibres, Nasmyth), to be, in fact, 
the nuclei of the ivory cells, the interfibrous sub- 
stance being the rest of the cell filled with calca- 
reous matter. In the natural state of the tooth all 
trace of the parietes or mode of connexion of the 
cells is lost, but after steeping in weak acid the 
cellular network is perfectly distinct. 

The enamel forms a crust over the whole exposed surface of the crown 
of the tooth to the commencement of its root ; it is thickest over the upper 
part of the crown, and becomes gradually thinner as it approaches the 
neck. It is composed of minute hexagonal crystalline fibres, resting by 
one extremity against the surface of the ivory, and constituting by the 
other the free surface of the crown. The fibres examined on the face of 
a longitudinal section have a waving arrangement, and consist, like those 
of ivory, of cells connected by their surfaces and ends and filled with cal- 
careous substance. When the latter is removed by weak acid, the ena- 
mel presents a delicate cellular net-work of animal matter. 

The cortical substance, or cementum, (substantia ostoidea,) forms a 
thin coating over the root of the tooth, from the termination of the enamel 
to the opening in the apex of the fang. In structure it is analogous to 
bone, and is characterized by the presence of numerous calcigerous cells 
and tubuli. The cementum increases in thickness with the advance of 
age, and gives rise to those exostosed appearances occasionally seen in the 
teeth of very old persons, or in those who have taken much mercury. In 
old age the cavitas pulpse is often found filled up and obliterated by 

* Microscopic section of a molar tooth. 1. Enamel with its columns and laminated 
structure. 2. Cortical substance or cementum on the outside of the fang. 3. Ivory, 
showing tubuli. 4. Foramen entering the dental cavity from the end of the fang. This 
fang has a bulbous enlargement in consequence of a hypertrophy of the cementum. 
5. Dental cavity. 6. A few osseous corpuscles in the ivory just under the enamel. 




DEVELOPMENT OF TEETH. 95 

osseous substance analogous to the cementum. Mr. Nasmyth has shown 
that this, like the other structures composing a tooth, is formed of cells 
having a reticular arrangement. 

Development. — The development of the teeth in the human subject has 
been successfully investigated by Mr. Goodsir, to whose interesting re- 
searches I am indebted for the following narrative : — * 

The inquiries of Mr. Goodsir commenced as early as the sixth week 
after conception, in an embryo, which measured seven lines and a half 
in length and weighed fifteen grains. At this early period each upper 
jaw presents two semicircular folds around its circumference ; the most 
external is the true lip ; the internal, the rudiment of the palate ; and be- 
tween these is a deep groove, lined by the common mucous membrane 
of the mouth. A little later, a ridge is developed from the floor of this 
groove in a direction from behind forwards, this is the rudiment of the 
external alveolus ; and the arrangement of the appearances from without 
inwards at this period is the following : — Most externally and forming the 
boundary of the mouth, is the lip ; next we find a deep groove, which 
separates the lip from ■ the future jaw ; then comes the external alveolar 
ridge ; fourthly, another groove, in which the germs of the teeth are de- 
veloped, the primitive dental groove ; fifthly, a rudiment of the internal 
alveolar ridge ; and, sixthly, the rudiment of the future palate bounding 
the whole internally. At the seventh week the germ of the first decidu- 
ous molar of the upper jaw has made its appearance, in the form of a 
" simple, free, granular papilla" of the mucous membrane, projecting 
from the floor of the primitive dental groove ; at the eighth week, the pa- 
pilla of the canine tooth is developed ; at the ninth week, the papillae 
of the four incisors (the middle preceding the lateral) appear ; and 
at the tenth week the papilla of the second molar is seen behind the ante- 
rior molar in the primitive dental groove. So that at this early period, 
viz. the tenth week, the papillae or germs of the whole ten deciduous teeth 
of the upper jaw are quite distinct. Those of the lower jaw are a little 
more tardy ; the papilla of the first molar is merely a slight bulging at the 
seventh week, and the tenth papilla is not apparent until the eleventh 
week. 

From about the eighth week the primitive dental groove becomes con- 
tracted before and behind the first deciduous molar, and laminae of the 
mucous membrane are developed around the other papillae, which increase 
in growth and enclose the papillae in follicles with open mouths. At the 
tenth week the follicle of the first molar is completed, then that of the 
canine ; during the eleventh and twelfth weeks the follicles of the incisors 
succeed, and at the thirteenth week the follicle of the posterior deciduous 
molar. 

During the thirteenth week the papillae undergo an alteration of form, 
and assume the shape of the teeth they are intended to represent. And 
at the same time small membranous processes are developed from the 
mouths of the follicles ; these processes are intended to serve the purpose 
of opercula to the follicles, and they correspond in shape with the form 
of the crowns of the appertaining teeth. To the follicles of the incisor 
teeth there are two opercula ; to the canine, three ; and to the molars a 
number relative to the number of their tubercles, either four or five. Dur- 

* " On the Origin and Development of the Pulps and Sacs of the Human Teeth," by 
John Goodsir, jun., in the Edinburgh Medical and Surgical Journal, January, 1839. 



96 DEVELOPMENT OF TEETH. 

ing the fourteenth and fifteenth weeks the opercula have completely closed 
the follicles, so as to convert them into dental sacs, and at the same time 
the papillae have become pulps. 

The deep portion of the primitive dental groove, viz. that which contains 
the dental sacs of the deciduous teeth, being thus closed in, the remaining 
portion, that which is nearer the surface of the gum, is still left open, and 
to this Mr. Goodsir has given the title of secondary dental groove ; as it 
serves for the development of all the permanent teeth, with the exception 
of the anterior molars. During the fourteenth and fifteenth weeks small 
lunated inflections of the mucous membrane are formed, immediately to 
the inner side of the closing opercula of the deciduous dental follicles, 
commencing behind the incisors and proceeding onwards through the rest; 
these are the rudiments of the .follicles or cavities of reserve of the four 
permanent incisors, two permanent canines, and the four bicuspides. As 
the secondary dental groove gradually closes, these follicular inflections 
of the mucous membrane are converted into closed cavities of reserve, 
which recede from the surface of the gum and lie immediately to the 
inner side and in close contact with the dental sacs of the deciduous teeth, 
being enclosed in their submucous cellular tissue. At about the fifth 
month the anterior of these cavities of reserve dilate at their distal extre- 
mities, and a fold or papilla projects into their fundus, constituting the 
rudiment of the germ of the permanent tooth ; at the same time two small 
opercular folds are produced at their proximal or small extremities, and 
convert them into true dental sacs. 

During the fifth month the posterior part of the primitive dental groove 
behind the sac of the last deciduous tooth has remained open, and in it 
has developed the papilla and follicle of the first permanent molar. Upon 
the closure of this follicle by its opercula, the secondary dental groove 
upon the summit of its crown forms a large cavity of reserve, lying in 
contact with the dental sac upon the one side and with the gum on the 
superficial side. At this period the deciduous teeth, and the sacs of the 
ten anterior permanent teeth, increase so much in size, without a corre- 
sponding lengthening of the jaws, that the first permanent molars are gra- 
dually pressed backwards and upwards into the maxillary tuberosity in 
the upper jaw, and into the base of the coronoid process of the lower jaw ; 
a position which they occupy at the eighth and ninth months of fcetal life. 
In the infant of seven or eight months the jaws have grown in length, and 
the first permanent molar returns to its proper position in the dental range. 
The cavity of reserve, which has been previously elongated by the upward 
movement of the first permanent molar, now dilates into the cavity which 
that tooth has just quitted ; a papilla is developed from its fundus, the 
cavity becomes constricted, and the dental sac of the second molar tooth 
is formed, still leaving a portion of the great cavity of reserve in connexion 
with the superficial side of the sac. As the jaws continue to grow in 
length, the second permanent dental sac descends from its elevated posi- 
tion and advances forwards into the dental range, following the same 
curve with the first permanent molar. The remainder of the cavity of 
reserve, already lengthened backwards by the previous position of the 
second molar, again dilates for the last time, developes a papilla and sac 
in the same manner with the preceding, and forms the third permanent 
molar or wisdom tooth, which at the age of nineteen or twenty, upon the 



GROWTH OF TEETH. 97 

increased growth of the jaw, follows the course of the first and second 
molars into the dental range. 

From a consideration of the foregoing phenomena, Mr. Goodsir has 
divided the process of dentition into three natural stages: — 1. follicular; 
2. saccular ; 3. eruptive. The first, or follicular stage, he makes to 
include all the changes which take place from the first appearance- of the 
dental groove and papillae to the closure of their follicles ; occupying a 
period which extends from the sixth week to the fourth or fifth month of 
intra-uterine existence. The second, or saccular stage, comprises the 
period when the follicles are shut sacs, and the included papillae pulps : 
it commences at the fourth and fifth months of intra-uterine existence, and 
terminates for the median incisors, at the seventh or eighth month of 
infantile life, and for the wisdom teeth at about the twenty-first year. 
The third, or eruptive stage, includes the completion of the teeth, the 
eruption and shedding of the temporary set, the eruption of the perma- 
nent, and the necessary changes in the alveolar processes. It extends 
from the seventh month till the twenty-first year. 

"The anterior permanent molar" says Mr. Goodsir, " is the most 
remarkable tooth in man, as it forms a transition between the milk and the 
permanent set." If considered anatomically, i. e. in its development 
from the primitive dental groove, by a papilla and follicle, " it is decidedly 
a milk tooth ;" if physiologically, " as the most efficient grinder in the 
adult mouth, we must consider it a permanent tooth." " It is a curious 
circumstance, and one which will readily suggest itself to the surgeon, 
that laying out of view the wisdom teeth, which sometimes decay at an 
early period from other causes, the anterior molars are the permanent teeth 
which most frequently give way first, and in the most symmetrical manner 
and at the same time, and frequently before the milk set." 

Growth of Teeth. — Immediately that the dental follicles have been 
closed by their opercula, the pulps become moulded into the form of the 
future teeth : and the bases of the molars divided into two or three por- 
tions representing the future fangs. The dental sac is composed of two 
layers, an internal or vascular layer, which was originally a part of the 
mucous surface of the mouth, and a cellulo-fibrous layer, analogous to the 
corium of the mucous membrane. Upon the formation of this sac by the 
closure of the follicle, the mucous membrane resembles a serous mem- 
brane in being a shut sac, and may be considered as consisting of a tunica 
propria, which invests the pulp ; and a tunica reflexa, which is adherent 
by its outer surface with the structures in the jaw, and by the inner surface 
is free, being separated from the pulp by an intervening cavity. As soon 
as the moulding of the pulp has commenced, this cavity increases and 
becomes filled with a gelatinous granular 
substance, the enamel organ, which is ad- 
herent to the whole internal surface of the 
tunica reflexa, but not to the tunica propria 
and pulp. At the same period, viz., dur- 
ing the fourth or fifth month, a thin lamina 
of ivory is formed by the pulp, and occu- 
pies its most prominent point ; if the tooth 

* a. Capsule of a temporary incisor with the rudiment of the corresponding perma 
nent tooth attached, b. Capsule of a molar in the same state. A part of the gum h 
seen above it and in contact. 

9 G 




98 TEETH — ERUPTION. 

be incisor or canine, the newly-formed layer has the figure of a small 
hollow cone ; if molar, there will be four or five small cones correspond- 
ing with the number of tubercles in its crown. These cones are united 
by the formation of additional layers, the pulp becomes gradually sur- 
rounded and diminishes in size, evolving fresh layers during its retreat 
into the jaws until the entire tooth with its fangs is completed, and the 
small cavitas pulpse of the perfect tooth alone remains, communicating 
through the opening in the apex of each fang with the dental vessels and 
nerves. The number of roots appears to depend upon the number of 
nervous filaments sent to each pulp. When the formation of the ivory 
has commenced, the enamel organ becomes transformed into a laminated 
tissue, corresponding with the direction of the fibres of the enamel, and 
the crystalline substance of the enamel is secreted into its meshes by the 
vascular lining of the sac. 

The cementum appears to be formed at a later period of life, either by a 
deposition of osseous substance by that portion of the dental sac, which 
continues to enclose the fang, and acts as its periosteum, or by the con- 
version of that membrane itself into bone ; the former supposition is the 
more probable. 

The formation of ivory commences in the first permanent molar pre- 
viously to birth. 

Eruption. — When the crown of the tooth has been formed and coated 
with enamel, and the fang has grown to the bottom of its socket by the 
progressive lengthening of the pulp, the formation of ivory, and the ad- 
hesion of the ivory to the contiguous portion of the sac, the pressure of the 
socket causes the reflected portion of the sac and the edge of the tooth to 
approach, and the latter to pass through the gum. The sac has thereby 
resumed* its original follicular condition, and has become continuous with 
the mucous membrane of the mouth. The opened sac now begins to 
shorten more rapidly than the fang lengthens, and the tooth is quickly 
drawn upwards by the contraction, leaving a space between the extremity 
of the unfinished root and the bottom of the socket, in which the growth 
and completion of the fang is more speedily effected. 

During the changes which have here been described as taking place 
among the dental sacs contained within the jaws, the septa between the 
sacs, which at first were composed of spongy tissue, soon became fibrous, 
and were afterwards formed of bone, which was developed from the sur- 
face and proceeded by degrees more deeply into the jaws, to constitute 
the alveoli. The sacs of the ten anterior permanent teeth, at first enclosed 
in the submucous cellular tissue of the deciduous dental sacs, and received 
Fig. 47,-j- during their growth into crypts situated behind the deciduous 
teeth, advanced by degrees beneath the fangs of those teeth, 
and became separated from them by distinct osseous alveoli. 
The necks of the sacs of the permanent teeth, by which they 
originally communicated with the mucous lining of the second- 
ary groove, still exist, in the form of minute obliterated cords, 
separated from the deciduous teeth by their alveolus, but com- 
municating through a minute osseous canal with the fibrous 
tissue of the palate, immediately behind the corresponding de- 

* Mr. Nasmyth is of opinion that it is "by a process of absorption, and not of disrup- 
tion, that the tooth is emancipated." Medico-chirurgical Transactions. 1839. 

f Temporary tooth with the capsule of its permanent successor attached to it by th«s 
gubernaculum dentis. 




OS HYOIDES. 99 

ciduous teeth. "These cords and foramina are not obliterated in the 
child,'' says Mr. Goodsir, "either because the cords are to become 
useful as ' gubernacula' and the canals as ' itinera dentium;"* or, much 
more probably, in virtue of a law, which appears to be a general one in the 
development of animal bodies, viz. that parts, or organs, which have once 
acted an important part, however atrophied they may afterwards become, yet 
never altogether disappear, so long as they do not interfere with other parts 
or Junctions." 

Succession. — The periods of appearance of the teeth are extremely irre- 
gular ; it is necessary, therefore, to have recourse to an average, which, 
for the temporary teeth, may be stated as follows, the teeth of the lower 
jaw preceding those of the upper by a short interval : — 

7th month, two middle incisors. 18th month, canine. 

9th month, two lateral incisors. 24th month, two last molares. 

12th month, first molares. 

The periods for the permanent teeth are, 

6| year, first molares. 10th year, second bicuspides. 

7th year, two middle incisors. 11th to 12th year, canine. 

8th year, two lateral incisors. 12th to 13th year, second molares. 

9th year, first bicuspides. 17th to 21st year, last molares. 

OS HYOIDES. 

The os hyoides forms the second arch developed from the cranium, and 
gives support to the tongue, and attachment to numerous muscles in the 
neck. It is named from its resemblance to the Greek letter u, and consists 
of a central portion or body, of two larger cornua, which project backwards 
from the body ; and two lesser cornua, which ascend from the angles of 
union between the body and the greater cornua. 

The body is somewhat quadrilateral, rough 
and convex on its antero-superior surface, by Flg " 4S * 

which it gives attachment to muscles ; concave 
and smooth on the postero-inferior surface, by 
which it lies in contact with the thyro-hyoidean 
membrane. The greater cornua are flattened 
from above downwards, and terminated posteri- 
orly by a tubercle ; and the lesser cornua, conical 
in form, give attachment to the stylo-hyoid liga- 
ments. In early age and in the adult, the cornua are connected with the 
body by cartilaginous surfaces and ligamentous fibres ; but in old age they 
become united by bone. 

Development. — By Jive centres, one for the body, and one for each 
cornu. Ossification commences in the greater cornua during the last 
month of foetal life, and in the lesser cornua and body soon after birth. 

Attachment of Muscles. — To eleven pairs ; sterno-hyoid, thyro-hyoid, 
omo-hyoid, pulley of the digastricus, stylo-hyoid, mylo-hyoid, genio- 
hyoid, genio-hyo-glossus, hyo-glossus, lingualis, and middle constrictor 
of the pharynx. It also gives attachment to the stylo-hyoid, thyro-hyoid, 
and hyo-epiglottic ligaments, and to the thyro-hyoidean membrane. 

* The os hyoides seen from before. 1. The antero-superior, or convex side of the 
body. 2. The great cornu of the left side. 3. The lesser cornu of the same side. The 
cornua were ossified to the body of the bone in the specimen from which this figure was 
drawn. 




100 STERNUM. 



THORAX AND UPPER EXTREMITY. 

The bones of the thorax are the sternum and ribs ; and, of the upper 
extremity, the clavicle, scapula, humerus, ulna and radius, bones of the 
carpus, metacarpus, and phalanges. 

Sternum. — The sternum (fig. 49) is situated in the middle line of the 
front of the chest, and is oblique in direction, the superior end lying within 
a few inches of the vertebral column, and the inferior being projected for- 
wards so as to be placed at a considerable distance from the spine. The 
bone is flat or slightly concave in front, and marked by five transverse 
lines which indicate its original subdivision into six pieces. It is convex 
behind, broad and thick above, flattened and pointed below, and is divisible 
in the adult into three pieces, superior, middle, and inferior. 

The superior piece, or manubrium, is nearly quadrilateral ; it is broad 
and thick above, where it presents a concave border (incisura semilu- 
naris), and narrow at its junction with the middle piece. At each supe- 
rior angle is a deep articular depression (incisura clavicularis) for the 
clavicle, and on either side two notches, for the articulation of the carti- 
lage of the first rib, and one half of the second. 

The middle piece, or body, considerably longer than the superior, is 
broad in the middle, and somewhat narrower at each extremity. It pre- 
sents at either side six articular notches, for the lower half of the second 
rib, the four next ribs, and the upper half of the seventh. This piece is 
sometimes perforated by an opening of various magnitude, resulting from 
arrest of development. 

The inferior piece (ensiform or xiphoid cartilage) is the smallest of the 
three, often merely cartilaginous, and very various in appearance, being 
sometimes pointed, at other times broad and thin, and at other times 
again, perforated by a round hole, or bifid. It presents a notch at 
each side for the articulation of the lower half of the cartilage of the 
seventh rib. 

Development. — By a variable number of centres, generally ten, namely, 
two for the manubrium ; one (sometimes two) for the first piece of the 
body, two for each of the remaining pieces, and one for the ensiform car- 
tilage. Ossification commences towards the end of the fifth month in the 
manubrium, the two pieces for this part being placed one above the other. 
At about the same time the centres for the first and second pieces of the 
body are apparent ; the centres for the third piece of the body appear a 
few months later, and those for the fourth piece soon after birth. The 
osseous centre for the ensiform cartilage is so variable in its advent, that 
it may be present at any period between the third and eighteenth year. 
The double centres for the body of the sternum are disposed side by side 
in pairs, and it is the irregular union of these pairs in the last three pieces 
of the body that gives rise to the large aperture occasionally seen in the 
sternum, towards its lower part. Union of the pieces of the sternum 
commences from below and proceeds upwards ; the fourth and the third 
unite at about puberty, the third and the second between twenty and 
twenty-five, and the second and the first between twenty-five and thirty. 
The ensiform appendix becomes joined to the body of the sternum at 
forty or fifty years ; and the manubrium to the body only in very old age. 
Two small pisiform pieces have been described by Beclard and Breschet, 



RIBS — TRUE AND FALSE. 



101 



as being situated upon and somewhat behind each extremity of the inci- 
sura semilunaris of the upper border of the manubrium. These pre- 
sternal or supra-sternal pieces, which are by no means constant, appear at 
about the thirty-fifth year. Beclard considers them to be the analogue 
of the fourchette of birds, and Breschet as the sternal ends of the cer- 
vical rib. 

Articulations. — With sixteen bones ; viz. with the clavicle and the seven 
true ribs, at each side. 

Attachment of Muscles. — To nine pairs and one single muscle ; viz. 
to the pectoralis major, sterno-mastoid, sterno-hyoid, sterno-thyroid, tri- 
angularis sterni, aponeurosis of the obliquus externus, internus, and trans- 
versalis muscles, rectus, and diaphragm. 

Ribs. — The ribs are twelve in number at each side ; the first seven are 
connected with the sternum, and hence named sternal or true ribs ; the 
remaining five are the asternal or false 
ribs ; and the last two shorter than the 



Fig. 49." 



rest, and free at their extremities, are 
the floating ribs. The ribs increase 
in length from the first to the eighth, 
whence they again diminish to the 
twelfth ; in breadth they diminish gra- 
dually from the first to the last, and 
with the exception of the last two 
are broader at the anterior than at the 
posterior end. The first rib is hori- 
zontal in its direction ; all the rest are 
oblique, so that the anterior extremity 
falls considerably below the posterior. 
Each rib presents an external and in- 
ternal surface, a superior and inferior 
border, and two extremities ; it is 
curved to correspond with the arch 
of the thorax, and twisted upon itself, 
so that, when laid on its side, one 
end is tilted up, while the other rests upon the surface. 

The external surface is convex, and marked by the attachment oi 
muscles; the internal is flat, and corresponds with the pleura; the superior 
border is rounded ; and the inferior sharp, and grooved upon its inner 
side, for the attachment of the intercostal muscles, f Near its vertebral 
extremity, the rib is suddenly bent upon itself; and opposite the bend, 
upon the external surface, is a rough oblique ridge, which gives attach- 
ment to a tendon of the sacro-lumbalis muscle, and is called the angle. 
The distance between the vertebral extremity and the angle increases 
gradually, from the second to the eleventh rib. Beyond the angle is a 

* An anterior view of the thorax. 1. The superior piece of the sternum. 2. The 
middle piece. 3. The inferior piece, or ensiform cartilage. 4. The first dorsal vertebra. 
5. The last dorsal vertebra. 6. The first rib. 7. Its head. 8. Its neck, resting against 
the transverse process of the first dorsal vertebra. 9. Its tubercle. 10. The seventh or 
last true rib. 11. The costal cartilages of the true ribs. 12. The last two false ribs or 
floating ribs. 13. The groove along the lower border of the rib. 

-f- This groove is commonly described as supporting the intercostal artery, vein, and 
nerve, but this is not the case. 




102 COSTAL CARTILAGES. 

rough elevation, the tubercle; and immediately at the base and under 
side of the tubercle a smooth surface for articulation with the extremity 
of the transverse process of the corresponding vertebra. The vertebral 
end of the rib is somewhat expanded, and is termed the head, and lhat 
portion between the head and the tubercle is the neck. On the extremity 
of the head is an oval smooth surface, divided by a transverse ridge into 
two facets, for articulation with two contiguous vertebrae. The posterior 
surface of the neck is rough, for the attachment of the middle costo-trans- 
verse ligament ; and upon its upper border is a crest, which gives attach- 
ment to the anterior costo-transverse ligament. The sternal extremity is 
flattened, and presents an oval depression, into which the costal cartilage 
is received. 

The ribs that demand especial consideration are the first, tenth, eleventh, 
and twelfth. 

The first is the shortest rib; it is broad and flat, and placed horizon- 
tally at the upper part of the thorax, the surfaces looking upwards and 
downwards, in place of forwards and backwards as in the other ribs. At 
about the anterior third of the upper surface of the bone, and near its in- 
ternal border, is a tubercle which gives attachment to the scalenus anticus 
muscle, and immediately before and behind this tubercle, a shallow ob- 
lique groove, the former for the subclavian vein, and the latter for the 
subclavian artery. Near the posterior extremity of the bone is a thick and 
prominent tubercle, with a smooth articular surface for the transverse pro- 
cess of the first dorsal vertebra. There is no angle. Beyond the tuber- 
osity is a narrow constricted neck ; and at the extremity, a head, present- 
ing a single articular surface. The second rib approaches in some of its 
characters to the first. 

The tenth rib has a single articular surface on its head. 

The eleventh and twelfth have each a single articular surface on the 
head, no neck or tubercle, and are pointed at the free extremity. The 
eleventh has a slight ridge, representing the angle, and a shallow groove 
on the lower border ; the twelfth has neither. 

Costal Cartilages. — The costal cartilages serve to prolong the ribs 
forwards to the anterior part of the chest, and contribute mainly to the 
elasticity of the thorax. They are broad at their attachment to the ribs, 
and taper slightly towards the opposite extremity ; they diminish gradually 
in breadth from the first to the last ; in length they increase from the first 
to the seventh, and then decrease to the last. The cartilages of the first 
two ribs are horizontal in direction, the rest incline more and more up- 
wards. In advanced age the costal cartilages are more or less converted 
into bone, this change taking place earlier in the male than in the female. 

The first seven cartilages articulate with the sternum ; the three next 
with the lower border of the cartilage immediately preceding, while the 
last two lie free between the abdominal muscles. All the cartilages of the 
false ribs terminate by pointed extremities. 

Development. — The ribs are developed by three centres ; one for the 
central part, one for the head, and one for the tubercle. The last two 
have no centre for the tubercle. Ossification commences in the body 
somewhat before its appearance in the vertebras ; the epiphysal centres for 
the head and tubercle appear between sixteen and twenty, and are conso- 
lidated with the rest of the bone at twenty-five. 



CLAVICLE — SCAPULA. 103 

.Articulations. — Each rib articulates with two vertebra?, and one costal 
cartilage, with the exception of the first, tenth, eleventh, and twelfth, 
which articulate each with a single vertebra only. 

Attachment of Muscles. — To the ribs and their cartilages are attached 
twenty-two pairs, and one single muscle. To the cartilages, the subcla- 
vius, sterno-thyroid, pectoralis major, internal oblique, rectus, transversa- 
lis, diaphragm, triangularis sterni, internal and external intercostals. To 
the ribs, the intercostal muscles, scalenus anticus, scalenus posticus, pec- 
toralis minor, serratus magnus, obliquus externus, obliquus internus, latis- 
simus dorsi, quadratus lumborum, serratus posticus superior, serratus pos- 
ticus inferior, sacro-lumbalis, longissimus dorsi, cervicalis ascendens, leva- 
tores costarum, transversalis, and diaphragm. 

4 

Clavicle. — The clavicle is a long bone shaped like the italic letter f 
and extended across the upper part of the side of the chest from the upper 
piece of the sternum to the point of the shoulder, where it articulates with 
the scapula. In position it is very slightly oblique, the sternal end being 
somewhat lower and more anterior than the scapular, and the curves are 
so disposed that at the sternal end the convexity, and at the scapular the 
concavity, is directed forwards. The sternal half of the bone is rounded 
or irregularly quadrilateral, and terminates in a broad articular surface. 
The scapular half is flattened from above downwards, and broad at its 
extremity, the articular surface occupying only part of its extent. The 
upper surface is smooth and convex, and partly subcutaneous ; while the 
under surface is rough and depressed, for the insertion of the subclavius 
muscle. At the sternal extremity of the under surface is a very rough 
prominence, which gives attachment to the rhomboid ligament ; and at 
the other extremity a rough tubercle and ridge, for the coraco-clavicular 
ligament. The opening for the nutritious vessels is seen upon the under 
surface of the bone. 

Development. — By two centres; one for the shaft and one for the sternal 
extremity ; the former appearing before any other bone of the skeleton, 
the latter between fifteen and eighteen. 

Articulations. — With the sternum and scapula. 

Attachment of Muscles. — To six ; the stemo-mastoid, trapezius, pecto- 
ralis major, deltoid, subclavius, and sterno-hyoid. 

Scapula. — The scapula is a flat triangular bone, situated upon the pos- 
terior aspect and side of the thorax occupying the space from the second 
to the seventh rib. It is divisible into an anterior and posterior surface, 
superior, inferior, and posterior border, anterior, superior, and inferior 
angle, and processes. 

The anterior surface or subscapular fossa, is concave and irregular, and 
marked by several oblique ridges which have a direction upwards and 
outwards. The whole concavity is occupied by the subscapulars muscle, 
with the exception of a small triangular portion near the superior angle. 
The posterior surface or dorsum is convex, and unequally divided into 
two portions by the spine ; that portion above the spine is the supra-spin- 
ous fossa ; and that below, the infra-spinous fossa. 

The superior border is the shortest of the three : it is thin and concave, 
and terminated at one extremity by the superior angle, and at the other by 
the coracoid process. At its inner termination, and formed partly by the 



104 



SCAPULA. 



Fig. 50. 



base of the coracoid process, is the supra-scapular notch, for the trans- 
mission of the supra-scapular nerve. 

The inferior or axillary border is thick, and marked by several grooves 
and depressions ; it terminates superiorly at the glenoid cavity, and infe- 
riorly at the inferior angle. Immediately below the glenoid cavity is a 
rough ridge, which gives origin to the long head of the triceps muscle. 
Upon the posterior surface of the border is a depression for the teres mi- 
nor ; and upon its anterior surface a deeper groove for the teres major ; 
near the inferior angle is a projecting lip, which increases the surface of 
origin of the latter muscle. 

The posterior border ', or base, the longest of the three, is turned towards 
the vertebral column. It is intermediate in thickness between the supe- 
rior and inferior, and convex, being considerably inflected outwards 
towards the superior angle. 

The anterior angle is the thickest part of the bone, and forms the head 
of the scapula; it is immediately surrounded by a constricted portion, the 

neck. The head presents a shallow pyriform 
articular surface, the glenoid cavity, having 
the pointed extremity upwards ; and at its 
apex is a rough depression, which gives at- 
tachment to the long tendon of the biceps. 
The superior angle is thin and pointed. 
The inferior angle is thick, and smooth upon 
the external surface for the origin of the teres 
2J major and for a large bursa over which the 
upper border of the latissimus dorsi muscle 
plays. 

The spine of the scapula, triangular in 
form, crosses the upper part of its dorsum ; 
it commences at the posterior border by a 
smooth triangular surface over w T hich the 
trapezius glides upon a bursa, and terminates 
at the point of the shoulder in the acromion 
process. The upper border of the spine is 
rough and subcutaneous, and gives attach- 
ment by two projecting lips to the trapezius and deltoid muscles ; the sur- 
faces of the spine enter into the formation of the supra and infra-spinous 
fossae. The nutritious foramina of the scapula are situated in the base of 
the spine. 

The acromion is somewhat triangular and flattened from above down- 
wards ; it overhangs the glenoid cavity, the upper surface being rough 
and subcutaneous, the lower smooth and corresponding with the shoulder- 
joint. Near its extremity, upon the anterior border, is an oval articular 
surface, for the end of the clavicle. 

The coracoid process is a thick, round, and curved process of bone, 
arising from the upper part of the neck of the scapula, and over arching 

* A posterior view of the scapula. 1. The supra-spinous fossa. 2. The infra-spinous 
fossa. 3. The superior border. 4. The supra-scapular notch. 5. The anterior or axil- 
lary border. 6. The head of the scapula and glenoid cavity. 7. The inferior angle. 
8. The neck of the scapula, the ridge opposite the number gives origin to the long head 
of the triceps. 9. The posterior border or base of the scapula. 10. The spine. 11. The 
triangular smooth surface, over which the tendon of the trapezius glides. 12. The acro- 
mion process. 13. One of the nutritious foramina. 14. The caracoid process. 




HUMERUS. 105 

the glenoid cavity. It is about two inches in length and very strong ; it 
gives attachment to several ligaments and muscles. 

Development. — By six centres ; one for the body, one for the coracoid 
process, two for the acromion, one for the inferior angle, and one for the 
posterior border. The ossific centre for the body appears in the infra- 
spinous fossa at about the same time with the ossification of the vertebra? ; 
for the coracoid process during the first year ; the acromion process at 
puberty; the inferior angle in the fifteenth year; and the posterior 
border at seventeen or eighteen. Union between the coracoid process 
and body takes place during the fifteenth year ; the bone is not complete 
till manhood. 

Articulations. — With the clavicle and humerus. 

Attachment of Muscles. — To sixteen ; by its anterior surface to the sub- 
scapulars ; posterior surface, supra-spinatus and infra-spinatus ; superior 
border, omo-hyoid ; posterior border, levator anguli scapulae, rhomboideus 
minor, rhomboideus major, and serratus magnus ; anterior border, long 
head of the triceps, teres minor, and teres major ; upper angle of the 
glenoid cavity, to the long tendon of the biceps ; spine and acromion to 
the trapezius and deltoid ; coracoid process, to the pectoralis minor, short 
head of the biceps, and coraco-brachialis. The ligaments attached to the 
coracoid process are, the coracoid, coracd-clavicular, and coraco-humeral, 
and the costo-coracoid membrane. 

Humerus. — The humerus is a long bone divisible into a shaft and two 
extremities. 

The superior extremity presents a rounded head; a constriction imme- 
diately around the base of the head, the neck; a greater and a lesser 
tuberosity. The greater tuberosity is situated most externally, and is 
separated from the lesser by a vertical furrow, the bicipital groove , which 
lodges the long tendon of the biceps. The edges of this groove below 
the head of the bone are raised and rough, and are called the anterior and 
posterior bicipital ridge ; the former serves for ^e insertion of the pecto- 
ralis major muscle, and the latter of the latissim dorsi and teres major. 

The constriction of the bone below the tubero jes is the surgical neck, 
and is so named, in contradistinction to the trvr. neck, from being the 
seat of the accident called by surgical writers fracture of the neck of the 
humerus. 

The shaft of the bone is prismoid at its upper part, and flattened from 
before backwards below. Upon its outer side, at about its middle, is a 
rough triangular eminence, which gives insertion to the deltoid ; and im- 
mediately on each side of this eminence is a smooth depression, corres- 
ponding with the two heads of the brachialis anticus. Upon the inner 
side of the middle of the shaft is a ridge, for the attachment of the coraco- 
brachialis muscle ; and behind, an oblique and shallow groove, which 
lodges the musculo-spiral nerve and superior profunda artery. The 
foramen for the medullary vessels is situated upon the inner surface of the 
shaft of the bone a little below the coraco-brachial ridge ; it is directed 
downwards. 

The lower extremity is flattened from before backwards, and is termi- 
nated inferiorly by a long articular surface, divided into two parts by an 
elevated ridge. The external portion of the articular surface is a rounded 
protuberance, eminentia capitata, which articulates with the cup-shaped 



106 



ULNA. 



Fig. 51.« depression on the head of the radius ; the internal portion 
is a concave and pulley-like surface, trochlea, which arti- 
culates with the ulna. Projecting beyond the articular 
surface on each side are the external and internal condyles, 
the latter being considerably the longer ; and running up- 
wards from the condyles upon the borders of the bone are 
the condyloid ridges, of which the external is the most 
prominent. Immediately in front of the trochlea is a 
small depression for receiving the coronoid process of the 
ulna during flexion of the fore-arm ; and immediately be- 
hind it a large and deep fossa, for containing the olecra- 
non process in extension. 

Development. — By seven centres ; one for the shaft, one 
for the head, one for the tuberosities, one for the eminen- 
tia capitata, one for the trochlea, and one for each con- 
dyle, the internal preceding the external. Ossification 
commences in the diaphysis of the humerus soon after the 
clavicle ; in the head and tuberosities, during the second 
and third years of infantile life ; in the eminentia capitata 
and trochlea during the third and sixth years ; and in the 
condyles during the twelfth and fifteenth. The entire 
bone is consolidated at twenty. 

Articulations. — With the glenoid cavity of the sca- 
pula, and with the ulna and radius. 

Attachment of Muscles. — To twenty-four ; by the greater tuberosity to 
the supra-spinatus, infra-spinatus, and teres minor ; lesser tuberosity, sub- 
scapularis ; anterior bicipital ridge, pectoralis major ; posterior bicipital 
ridge and groove, teres major and latissimus dorsi ; shaft, external and 
internal heads of the triceps, deltoid, coraco-brachialis, and brachialis 
anticus ; external condyloid ridge and condyle (condylus extensorius), 
extensors and supinators of the fore-arm, viz. supinator longus, extensor 
carpi radialis longior, extensor carpi radialis brevior, extensor communis 
digitorum, extensor minimi digiti, extensor carpi ulnaris, anconeus, and 
supinator brevis ; internal condyle (condylus fexorius), flexors and one 
pronator, viz. pronator radii teres, flexor carpi radialis, palmaris longus, 
flexor sublimis digitorum, and flexor carpi ulnaris. 

Ulna. — The ulna is a long bone, divisible into a shaft and two extre- 
mities. The upper extremity is large, and forms principally the articula- 
tion of the elbow ; while the lower extremity is small, and excluded from 
the wrist-joint by an inter-articular fibro-cartilage. 

The superior extremity presents a semilunar concavity of large size, the 
greater sigmoid notch, for articulation with the humerus ; and upon the 
outer side a lesser sigmoid notch, which articulates with the head of the 
radius. Bounding the greater sigmoid notch posteriorly is the olecranon 
process ; and overhanging it in front, a pointed eminence with a rough 

* The humerus of the right side; its anterior surface. 1. The shaft of the bone. 2. 
The head. 3. The anatomical neck. 4. The greater tuberosity. 5. The lesser tube- 
rosity. 6. The bicipital groove. 7. The anterior bicipital ridge. 8. The posterior 
bicipital ridge. 9. The rough surface into which the deltoid is inserted. 10. The nu- 
tritious foramen. 11. The eminentia capitata. 12. The trochlea. 13. The external 
condyle. 14. The internal condyle. 15. The external condyloid ridge. 16. The inter 
nal condyloid ridge. 17. The fossa for the coronoid process of the ulna. 



RADIUS. 107 

triangular base, the coronoid process. Behind the lesser sigmoid notch, 
and extending downwards on the side of the olecranon, is a triangular 
uneven surface, for the anconeus muscle ; and upon the posterior surface 
of the olecranon a smooth triangular surface, which is subcutaneous. 

The shaft is prismoid in form, and presents three surfaces, anterior, 
posterior, and internal ; and three borders. The anterior surface is occu- 
pied by the flexor profundis digitorum for the upper three-fourths of its 
extent ; and below by a depression, for the pronator quadratus muscle. 
A little above its middle is the nutritious foramen, which is directed up- 
wards. Upon the posterior surface at the upper part of the bone is the 
triangular uneven depression for the anconeus muscle, bounded inferiorly 
by an oblique ridge which runs downwards from the posterior extremity 
of the lesser sigmoid notch. Below the ridge the surface is marked into 
several grooves, for the attachment of the extensor ossis metacarpi, exten- 
sor secundi internodii, and extensor indicis muscle. The internal surface 
is covered in for the greater part of its extent by the flexor profundis digi- 
torum. The anterior border is rounded, and gives origin by its lower 
fourth to the pronator quadratus ; the posterior is more prominent, and 
affords attachment to the flexor carpi ulnaris and extensor carpi ulnaris. 
At its upper extremity it expands into the triangular subcutaneous surface 
of the olecranon. The external or radial border is sharp and prominent, 
for the attachment of the interosseous membrane. 

The lower extremity terminates in a small rounded head, capitulum 
ulna, from the side of which projects the styloid process. The latter pre- 
sents a deep notch at its base for the attachment of the apex of the trian- 
gular interarticular cartilage, and by its point gives attachment to the 
internal lateral ligament. Upon the posterior surface of the head is a 
groove, for the tendon of the extensor carpi ulnaris ; and upon the side 
opposite to the styloid process a smooth surface, for articulation with the 
side of the radius. 

Development. — By three centres ; one for the shaft, one for the inferior 
extremity, and one for the olecranon. Ossification commences in the 
ulna shortly after the humerus and radius : the two ends of the bone are 
cartilaginous at birth. The centre for the lower end appears at about the 
fifth, and that for the olecranon about the seventh year. The bone is 
completed at about the twentieth year. 

Articulations. — With hoo bones ; the humerus and radius ; it is sepa- 
rated from the cuneiform bone of the carpus by the triangular interarticular 
cartilage. 

Attachment of Muscles. — To twelve ; by the olecranon, to the triceps 
extensor cubiti, one head of the flexor carpi ulnaris, and the anconeus ; 
by the coronoid process, to the brachialis anticus, pronator radii teres, 
flexor sublimis digitorum, and flexor profundus digitorum ; by the shaft, 
to the flexor profundus digitorum, flexor carpi ulnaris, pronator quadratus, 
anconeus, extensor carpi ulnaris, extensor ossis metacarpi pollicis, extensor 
secundi internodii pollicis, and extensor indicis. 

Radius. — The radius is the rotatory bone of the fore-arm ; it is divisible 
into a shaft and two extremities : unlike the ulna, its upper extremity is 
small, and merely accessory to the formation of the elbow-joint; while the 
lower extremity is large, and forms almost solely the joint of the wrist. 

The superior extremity, presents a rounded head, depressed upon its 



108 



RADIUS. 



Fig. 52* 




upper surface into a shallow cup. Around the margin of 
the head is a smooth articular surface, which is broad on 
the inner side, where it articulates with the lesser sigmoid 
notch of the ulna, and narrow in the rest of its circumfer- 
ence, to play in the orbicular ligament. Beneath the head 
is a round constricted neck ; and beneath the neck, on its 
internal aspect, a prominent process, the tuberosity. The 
surface of the tuberosity is partly smooth, and partly rough ; 
rough below, where it receives the attachment of the ten- 
don of the biceps ; and smooth above, where a bursa is 
interposed between the tendon and the bone. 

The shaft of the bone is prismoid, and presents three 
surfaces. The anterior surface is somewhat concave su- 
periorly, where it lodges the flexor longus pollicis ; and 
flat below, where it supports the pronator quadratus. At 
about the upper third of this surface is the nutritious fora- 
men, which is directed upwards. The posterior surface 
is round above, where it supports the supinator brevis 
muscle, and marked by several shallow oblique grooves 
below, which afford attachment to the extensor muscles 
of the thumb. The external surface is rounded and con- 
vex, and marked by an oblique ridge, which extends from 
the tuberosity to the styloid process at the lower extremity 
of the bone. Upon the inner margin of the bone is a sharp and prominent 
crest, which gives attachment to the interosseous membrane. The lower 
extremity of the radius is broad and triangular, and provided with two ar- 
ticular surfaces ; one at the side of the bone, which is concave to receive 
the rounded head of the ulna ; the other at the extremity, and marked by 
a slight ridge into two facets, one external and triangular, corresponding 
with the scaphoid ; the other square, with the semilunar bone. Upon the 
outer side of the extremity is a strong conical projection, the styloid process, 
which gives attachment by its base to the tendon of the supinator longus, 
and by its apex to the external lateral ligament of the wrist joint. The 
inner edge of the articular surface affords attachment to the base of the 
inter-articular cartilage of the ulna. 

Immediately in front of the styloid process is a groove, which lodges 
the tendons of the extensor ossis metacarpi pollicis, and extensor primi 
internodii ; and behind the process a broader groove, for the tendons of 
the extensor carpi radialis longior and brevior, and extensor secundi inter- 
nodii ; behind this is a prominent ridge, and a deep and narrow groove, 
for the tendon of the extensor indicis ; and still farther back, part of a 
broad groove, completed by the ulna, for the tendons of the extensor 
communis digitorum. 

Development. — By three centres ; one for the shaft, and one for each ex- 
tremity. Ossification commences in the shaft soon after the humerus, and 
before that in the ulna. The inferior centre appears during the second 

* The two bones of the fore-arm seen from the front. 1. The shaft of the ulna. 2. 
The greater sigmoid notch. 3. The lesser sigmoid notch, with which the head of the 
radius is articulated. 4. The olecranon process. 5. The coronoid process. 6. The nu- 
tritious foramen. 7. The sharp ridges upon the two bones to which the interosseous 
memhmne is attached. 8. The capitulum nlntr. 9. The styloid process. 10. The 
shaft of the radius. 11. Its head surrounded by the smooth border for articulation with 
the orbicular ligament. 12. The neek of the radius. 13. Its tuberosity. 14. The oblique 
line. 15. Tire lower extremity of the bone. 1G. Its styloid process. 



CARPUS SCAPHOID AND SEMILUNAR BONES. 



109 



year, and the superior about the seventh. The bone is perfected at 
twenty. 

Articulations. — With four bones; humerus, ulna, scaphoid, and semi- 
lunar. 

Attachment of Muscles. — To nine; by the tuberosity to the biceps ; by 
the oblique ridge to the supinator brevis, pronator radii teres, flexor sub- 
lines digitorum and pronator quadratus ; by the anterior surface, to the 
flexor longus pollicis and pronator quadratus ; by the posterior surface, to 
the extensor ossis metacarpi pollicis, and extensor primi internodii ; and 
by the styloid process, to the supinator longus. 

Carpus. — The bones of the carpus are eight in number ; they are ar- 
ranged in two rows. In the first row, commencing from the radial side, 
are the os scaphoides, semilunare, cuneiforme, pisiforme ; and in the se- 
cond row, in the same order, the os trapezium, trapezoides, os magnum, 
and unciforme. 

The Scaphoid bone is named from bearing some resemblance to the 
shape of a boat, being broad at one end, and narrowed like a prow at the 
opposite, concave on one side, and 6onvex upon the other. It is, how- 
ever, more similar in form to a cashew nut, flattened and concave upon 
one side. If carefully examined, it will be found to present a convex and 
a concave surface, a convex and a concave border, a broad end, and a nar- 
row and pointed extremity, the tuberosity. 

To ascertain to which hand the bone belongs, let the student hold it 
horizontally, so that the convex surface may look backwards (i. e. towards 
himself), and the convex border upwards: the broad extremity will indi- 
cate its appropriate hand ; if it be directed to the right, the bone belongs 
to the right ; and if to the left, to the left carpus. 

Articulations. — With Jive bones ; by its con- 
vex surface with the radius ; by its concave 
surface, with the os magnum and semilunare ; 
and by the extremity of its upper or dorsal 
border, with the trapezium and trapezoides. 

Attachments. — By its tuberosity to the ab- 
ductor pollicis, and anterior annular ligament. 

The Semilunar bone may be known by 
having a crescentic concavity, and a some- 
what crescentic outline. It presents for exami- 
nation four articular surfaces and two extremi- 
ties ; the articular surfaces are, one concave, 
one convex, and two lateral, one lateral surface 
being crescentic, the other nearly circular, and 
divided generally into two facets. The extre- 
mities are, one dorsal, which is quadrilateral, flat, and indented, for the 

* A diagram showing the dorsal surface of the bones of the carpus, witli their articu- 
lations. — The right hand. 2. The lower end of the radius. 1. The lower extremity 
of the ulna. 3. The inter-articular fibro-cartilage attached to the styloid process of the 
ulna, and to the margin of the articular surface of the radius. S. The scaphoid bone. 
L. The semilunare articulating with five bones. C. The cuneiforme, articulating with 
three bones. P. The pisiforme, articulating with the cuneiforme only. T. The first 
bone of the second row, — the trapezium, articulating with four bones. T. The second 
bone, — the trapezoides, articulating also with four bones. M. The os magnum, articu- 
lating with seven. U. The unciforme, articulating with five. 

10 



Fig. 53* 




HO CUNEIFORME — PISIFORME — TRAPEZIUM. 

attachment of ligaments ; the other palmar, which is convex, rounded, 
and of larger size. 

To determine to which hand it belongs, 'let the bone be held perpendi- 
cularly, so that the dorsal or flat extremity look upwards, and the convex 
side backwards (towards the holder). The circular lateral surface will 
point to the side corresponding with the hand to which the bone belongs. 

•Articulations. — With Jive bones, but occasionally with only four : by 
its convex surface, with the radius ; by its concave surface, with the os 
magnum ; by its crescentic lateral facet, with the scaphoid ; and by the 
circular surface, with the cuneiform bone and with the point of the unci- 
form. This surface is divided into two parts by a ridge when it articu- 
lates with the unciform as well as with the cuneiform bone. 

The Cuneiform bone, although somewhat wedge-shaped in form, may 
be best distinguished by a circular and isolated facet, which articulates 
with the pisiform bone. It presents for examination three surfaces , a base, 
and an apex. One surface is very rough and irregular ; the opposite forms 
a concave articular surface, while the third is partly rough and partly 
smooth, and presents that circular facet which is characteristic of the bone. 
The base is an articular surface, and the apex is round and pointed. 

To distinguish its appropriate hand, let the base be directed backwards 
and the pisiform facet upwards ; the concave articular surface will point 
to the hand to which the bone belongs. 

Articulations. — With three bones, and with the triangular fibro-cartilage. 
By the base, with the semilunare ; by the concave surface, with the unci- 
forme ; by the circular facet, with the pisiforme ; and by the superior angle 
of the rough surface, with the fibro-cartilage. 

The Pisiform bone maybe recognised by its small size, and by possess- 
ing a singular articular facet. If it be examined carefully it will be ob- 
served to present four sides and two extremities ; one side is articular, 
the smooth facet approaching nearer to the superior than the inferior ex- 
tremity. The side opposite to this is rounded, and the remaining sides 
are, one slightly concave, the other slightly convex. 

If the bone be held so that the articular facet shall look downwards and 
the extremity which overhangs the articular facet forwards, the concave 
side will point to the hand to which it belongs. 

Articulations. — With the cuneiform bone only. 

Attachments. — To two muscles, the flexor carpi ulnaris, and abductor 
minimi digiti ; and to the anterior annular ligament. 

The Trapezium (os multangulum majus) is too irregular in form to be 
compared to any known object; it may be distinguished by a deep 
groove, for the tendon of the flexor carpi radialis muscle. It is somewhat 
compressed, and may be divided into two surfaces which are smooth and 
articular, and three rough borders. One of the articular surfaces is oval, 
concave in one direction, and convex in the other (saddle-seat shaped) ; 
the other is marked into three facets. One of the borders presents the 
groove for the tendon of the flexor carpi radialis, which is surmounted by 
a prominent tubercle for the attachment of the annular ligament ; the other 
two borders are rough and form the outer side of the carpus. The grooved 
border is narrow at one extremity and broad at the other, where it pre- 
sents the groove and tubercle. 

If the bone be held so that the grooved border look upwards while the 
apex of this border be directed forwards, and the base with the tubercle 



TRAPEZOIDES — OS MAGNUM. 



Ill 



backwards, the concavo-convex surface will point to the hand to which 
the bone belongs. 

Articulations. — With four bones ; by the concavo-convex surface, with 
the metacarpal bone of the thumb ; and by the three facets of the other 
articular surface, with the scaphoid, trapezoid, and second metacarpal 
bone. 

Attachments. — To two muscles, abductor pollicis and flexor ossis meta- 
carpi ; and by the tubercle, to the annular ligament. 

The Trapezoides (os multangulum minus) is a small, oblong, and 
quadrilateral bone, bent near its middle upon itself (bean-shaped). It 
presents four articular surfaces and two extremities. One of the surfaces 
is concavo-convex, i. e. concave in one direction, and convex in the other; 
another, contiguous to the preceding, is concave, so as to be almost angu- 
lar in the middle, and is often marked by a small rough depression, for 
an interosseous ligament ; the two remaining sides are flat, and present 
nothing remarkable. One of the two extremities is broad and of large 
size, the dorsal ; the other, or palmar, is small and rough. 

If the bone be held perpendicularly, so that the broad extremity be up- 
wards, and the concavo-convex surface forwards, the angular concave 
surface will point to the hand to which the bone belongs. 

Articulations. — Withybwr bones; by the concavo-convex surface, with 
the second metacarpal bone ; by the angular concave surface, with the os 
magnum ; and by the other two surfaces, with the trapezium and scaphoid. 

Attachments. — To the flexor brevis pollicis muscle. 

The Os Magnum (capitatum) is the largest bone of the carpus, and is 
divisible into a body and head. The head is round for the greater part 
of its extent, but is flattened on one side. The 
body is irregularly quadrilateral, and presents four 
sides and a smooth extremity. Two of the sides 
are rough, the one being square and flat, the 
dorsal ; the other rounded and prominent, the 
palmar ; the other two sides are articular, the 
one being concave, the other convex. The ex- 
tremity is a triangular articular surface, divided 
into three facets. 

If the bone be held perpendicularly, so that 
the articular extremity look upwards and the 
broad dorsal surface backwards (towards the 
holder), the concave articular surface will point 
to the hand to which the bone belongs. 

Articulations. — With seven bones; by the 
rounded head, with the cup formed by the sca- 
phoid and semilunar bone ; by the side of the 
convex surface, with the trapezoides ; by the 
concave surface, with the unciforme ; and by 
the extremity, with the second, third, and fourth metacarpal bones. 

* The hand viewed upon its anterior or palmar aspect. 1. The scaphoid bone. 2. 
The semilunare. 3. The cuneiforme. 4. The pisiforme. 5. The trapezium. 6. The 
groove in the trapezium that lodges the tendon of the flexor carpi radialis. 7. The 
trapezoides. 8. The os magnum. 9. The unciforme. 10, 10. The five metacarpal 
bones. 11, 11. The first row of phalanges. 12, 12. The second row. 13, 13. The 
third row, or ungual phalanges. 14. The first phalanx of the thumb. 15. The second 
and last phalanx of the thumb. / 



Fig. 54* 




112 UNCIFORME — METACARPUS. 

Attachments. — To the flexor brevis pollicis muscle. 

The Unciforme is a triangular-shaped bone, remarkable for a long and 
curved process, which projects from its palmar aspect. It presents five 
surfaces ; — three articular, and two free. One of the articular surfaces is 
divided by a slight ridge into two facets ; the other two converge, and 
meet at a flattened angle.* One of the free surfaces, the dorsal, is rough 
and triangular ; the other, palmar, also triangular, but somewhat smaller, 
gives origin to the unciform process. 

If thebone be held perpendicularly, so that the articular surface with 
two facets look upwards, and the unciform process backwards (towards 
the holder), the concavity of the unciform process will point to the hand 
to which the bone belongs. 

Articulations. — With Jive bones ; by the two facets on its base, with the 
fourth and fifth metacarpal bones ; by the two lateral articulating surfaces, 
with the os magnum and cuneiforme ; and by the flattened angle of its 
apex, with the semilunare. 

Attachments. — To two muscles, abductor minimi digiti, and flexor 
brevis minimi digiti ; and by the hook-shaped process to the annular liga- 
ment. 

Development. — The bones of the carpus are each developed by a single 
centre ; they are cartilaginous at birth. Ossification commences towards 
the end of the first year in the os magnum and unciforme ; at the end of 
the third year in the cuneiforme ; during the fifth year in the trapezium 
and semilunare ; during the eighth, in the scaphoides ; the ninth, in the 
trapezoides : and the twelfth in the pisiforme. The latter bone is the last 
in the skeleton to ossify ; it is, in reality, a sesamoid bone of the tendon 
of the flexor carpi ulnaris. 

The number of articulations which each bone of the carpus presents 
with surrounding bones, may be expressed in figures, which will materially 
facilitate their recollection; the number for the first row is 5531, and for 
the second 4475. 

Metacarpus. — The bones of the metacarpus are five in number. They 
are long bones, divisible into a head, shaft, and base. 

The head is rounded at the extremity, and flattened at each side, for the 
insertion of strong ligaments ; the shaft is prismoid, and marked deeply 
on each side, for the attachment of the interossei muscles ; and the base 
is irregularly quadrilateral and rough, for the insertion of tendons and 
ligaments. The base presents three articular surfaces, one at each side, 
for the adjoining metacarpal bones ; and one at the extremity for the 
carpus. 

The metacarpal bone of the thumb is one-third shorter than the rest, 
flattened and broad on its dorsal aspect, and convex on its palmar side; 
the articular surface of the head is not so round as that of the other meta- 
carpal bones ; and the base has a single concavo-convex surface, to arti- 
culate with the similar surface of the trapezium. t 

The metacarpal bones of the different fingers may be distinguished by 
certain obvious characters. The base of the metacarpal bone of the index 
finger is the largest of the four, and presents four articular surfaces. That 
of the middle finger may be distinguished by a rounded projecting process 

* When the unciforme does not articulate with the semilunare, this angle is sharp 



PHALANGES. 113 

upon the radial side of its base, and two small circular facets upon its 
ulnar lateral surface. The base of the metacarpal bone of the ring-finger 
is small and square, and has two small circular facets to correspond with 
those of the middle metacarpal. The metacarpal bone of the little finger 
has only one lateral articular surface. 

Development. — By two centres ; one for the shaft, and one for the digi- 
tal extremity, with the exception of the metacarpal bone of the thumb, the 
epiphysis of which, like that of the phalanges, occupies the carpal end of 
the bone. Ossification of the metacarpal bones commences in the em- 
bryo between the tenth and twelfth week, that is, soon after the bones of 
the fore-arm. The epiphyses make their appearance at the end of the 
second, or early in the third year, and the bones are completed «t twenty. 

Articulations. — The first with the trapezium ; second, with the trape- 
zium, trapezoides, and os magnum, and with the middle metacarpal 
bone ; third, or middle, with the os magnum, and adjoining metacarpal 
bones ; fourth, with the os magnum and unciforme, and with the adjoin- 
ing metacarpal bones ; and, fifth, with the unciforme, and with the meta- 
carpal bone of the ring-finger. 

The figures resulting from the number of articulations which each 
metacarpal bone possesses, taken from the radial to the ulnar side, are 
13121. 

Attachment of Muscles. — To the metacarpal bone of the thumb, three, 
the flexor ossis metacarpi, extensor ossis metacarpi, and first dorsal inter- 
osseous ; of the index finger, five, the extensor carpi radialis longior, 
flexor carpi radialis, first and second dorsal interosseous, and first palmar 
interosseous; of the middle finger, four, the extensor carpi radialis bre- 
vior, adductor pollicis, and second and third dorsal interosseous ; of the 
ring finger, three, the third and fourth dorsal interosseous, and second 
palmar; and of the little finger, four, extensor carpi ulnaris, adductor 
minimi digiti, fourth dorsal, and third palmar interosseous. 

Phalanges. — The phalanges are the bones of the fingers ; they are 
named from their arrangement in rows, and are fourteen in number, three 
to each finger, and two to the thumb. In conformation they are long- 
bones, divisible into a shaft, and two extremities. 

The shaft is compressed from before backwards, convex on its poste- 
rior surface, and flat with raised edges in front. The metacarpal ex- 
tremity, or base, in the first row, is a simple concave articular surface, that 
in the other two rows a double concavity, separated by a slight ridge. 
The digital extremities of the first and second row present a pulley-like 
surface, concave in the middle, and convex on each side. The ungual 
extremity of the last phalanx is broad, rough, and expanded into a semi- 
lunar crest. 

Development. — By two centres ; one for the shaft, and one for the base. 
Ossification commences first in the third phalanges, then in the first, and 
lastly in the second. The period of commencement corresponds with 
that of the metacarpal bones. The epiphyses of the first row appear dur- 
ing the third or fourth year, those of the second row during the fourth or 
fifth, and of the last during the sixth or seventh. The phalanges are per- 
fected by the twentieth year. 

Articulations. — The first row, with the metacarpal bones and second 
10* H 



114 



OS INNOMINATUM — ILIUM. 



row of phalanges ; the second row, with the first and third; and the third, 
with the second row. 

Attachment of Muscles. — To the base of the first phalanx of the thumb 
four muscles, abductor pollicis, flexor brevis pollicis, adductor pollicis, 
and extensor primi internodii ; and to the second phalanx, two, the flexor 
longus pollicis, and extensor secundi internodii. To the first phalanx of 
the second, third, and fourth fingers, one dorsal and one palmar interos- 
seous, and to the first phalanx of the little finger, the abductor minimi 
digiti, flexor brevis minimi digiti, and one palmar interosseous. To the 
second phalanges, the flexor sublimis and extensor communis digitorum ; 
and to the last phalanges, the flexor profundus and extensor communis 
digitorum. 

PELVIS AND LOWER EXTREMITY. 

The bones of the pelvis are the two ossa innominata, the sacrum, and 
the coccyx ; and of the lower extremity, the femur, patella, tibia and 
fibula, tarsus, metatarsus, and phalanges. 

Fig. 55* Os Innominatum. — The os inno- 

minatum (os coxae) is an irregular 
flat bone, consisting in the young 
subject of three parts, which meet at 
the acetabulum. Hence it is usually 
described in the adult as divisible 
into three portions, ilium, ischium, 
and pubes. The ilium is the supe- 
rior, broad, and expanded portion 
which forms the prominence of the 
hip, and articulates with the sacrum. 
The ischium is the inferior and strong 
part of the bone oh which we sit. 
The os pubis is that portion which 
forms the front of the pelvis, and 
gives support to the external organs 
of generation. 

The Ilium may be described as 
divisible into an internal and external 
surface, a crest, and an anterior and posterior border. 

The internal surface is bounded above by the crest, below by a promi- 
nent line, the linea ilio-pectinea, and before and behind by the anterior 
and posterior borders ; it is concave and smooth for the anterior two-thirds 
of its extent, and lodges the iliacus muscle. The posterior third is rough, 
for articulation with the sacrum, and is divided by a deep groove into two 
parts ; an anterior or auricular portion, which is shaped like the pinna, 

*The os innominatum of the right side. 1. The ilium ; its external surface. 2. The 
ischium. 3 The os pubis. 4. The crest of the ilium. 5. The superior curved line. 
6. The inferior curved line. 7. The surface for the gluteus maximus. 8. The anterior 
superior spinous process. 9. The anterior inferior spinous process. 10. The posterior 
superior spinous process. 11. The posterior inferior spinous process. 12. The spine 
of the ischium. 13. The great sacro-ischiatic notch. 14. The lesser sacro-ischiatic 
notch. 15. The tuberosity of the ischium, showing its three facets. 16. The ramus of 
the ischium. 17. The body of the os pubis. 18. The ramus of the pubis. 19. The 
acetabulum. 20. The foramen thyroideum. 




ISCHIUM. 115 

and coated by cartilage in the fresh bone ; and a posterior portion, which 
is very rough and uneven for the attachment of interosseous ligaments. 

The external surface is uneven, partly convex, and partly concave ; it 
is bounded above by the crest ; below by a prominent arch, which forms 
the upper segment of the acetabulum ; and before and behind, hy the 
anterior and posterior borders. Crossing this surface in an arched direc- 
tion, from the anterior extremity of the crest to a notch upon the lower 
part of the posterior border, is a groove, which lodges the gluteal vessels 
and nerve, the superior curved line ; and below this, at a short distance, a 
rough ridge, the inferior curved line. The surface included between the 
superior curved line and the crest, gives origin to the gluteus medius 
muscle ; that between the curved lines, to the gluteus minimus ; and the 
rough interval between the inferior curved line and the arch of the aceta- 
bulum, to one head of the rectus. The posterior sixth of this surface is 
rough and raised, and gives origin to part of the gluteus maximus. 

The crest of the ilium is arched and curved in its direction like the 
italic letter/, being bent inwards at its anterior termination, and outwards 
towards the posterior. It is broad for the attachment of three planes of 
muscles, which are connected with its external and internal borders or lips, 
and with the intermediate space. 

The anterior border is marked by two projections, the anterior superior 
spinous process, which is the anterior termination of the crest, and the 
anterior inferior spinous process ; the two processes being separated by a 
notch for the attachment of the sartorius muscle. This border terminates 
inferiorly in the lip of the acetabulum. The posterior border also presents 
two projections, the posterior superior and the posterior inferior spinous ' 
process, separated by a notch. Inferiorly this border is broad and arched, 
and forms the upper part of the great sacro-ischiatic notch. 

The Ischium is divisible into a thick and solid portion, the body, and 
into a thin and ascending part, the ramus ; it may be considered also, for 
convenience of description, as presenting an external and internal surface, 
and three borders, posterior, inferior, and superior. 

The external surface is rough and uneven, for the attachment of muscles ; 
and broad and smooth above, where it enters into the formation of the 
acetabulum. Below the inferior lip of the acetabulum is a notch, which 
lodges the obturator externus muscle in its passage outwards to the tro- 
chanteric fossa of the femur. The internal surface is smooth, and some- 
what encroached upon at its posterior border by the spine. 

The posterior border of the ischium presents towards its middle a re- 
markable projection, the spine. Immediately above the spine is a notch 
of large size, the great sacro-ischiatic, and below the spine the lesser sacro- 
ischiatic notch ; the former being converted into a foramen by the lesser 
sacro-ischiatic ligament, gives passage to the pyriformis muscle, the gluteal 
vessels and nerve, pudic vessels and nerve, and ischiatic vessels and nerve; 
and the lesser, completed by the great sacro-ischiatic ligament, to the 
obturator internus muscle, and to the internal pudic vessels and nerve. 
The inferior border is thick and broad, and is called the tuberosity. The 
surface of the tuberosity is divided into three facets ; one anterior, which 
is rough for the origin of the semi-membranosus ; and two posterior, which 
are smooth, and separated by a slight ridge for the semi-tendinosus and 
biceps muscle. The inner margin of the tuberosity is bounded by a sharp 
ridge, which gives attachment to a prolongation of the great sacro-ischiatic 



116 OS PUBIS. 

ligament, and the outer margin by a prominent ridge, from which the 
quadratus femoris muscle arises. The superior border of the ischium is 
thin, and forms the lower circumference of the obturator foramen. The 
ramus of the ischium is continuous with the ramus of the pubis, and is 
slightly everted. 

The Os Pubis is divided into a horizontal portion or body (horizontal 
ramus of Albinus), and a descending portion or ramus ; it presents for 
examination an external and internal surface, a superior and inferior bor- 
der, and symphysis. 

The external surface is rough, for the attachment of muscles ; and pro- 
minent at its outer extremity, where it forms part of the acetabulum. The 
internal surface is smooth, and enters into the formation of the cavity of 
the pelvis. The superior border is marked by a rough ridge, the crest ; 
the inner termination of the crest is the angle; and the outer end, the spine 
or tubercle. Running outwards from the spine is a sharp ridge, the pecti- 
neal line, or linea ilio-pectinea, which marks the brim of the true pelvis. 
In front of the pectineal line is a smooth depression, which supports the 
femoral artery and vein, and a little more externally an elevated promi- 
nence, the ilio-pectineal eminence, which divides the surface for the femoral 
vessels, from another depression which overhangs the acetabulum, and 
lodges the psoas and iliacus muscles. The ilio-pectineal eminence more- 
over marks the junction of the pubes with the ilium. The inferior bordei 
is broad and deeply grooved, for the passage of the obturator vessels and 
nerve ; and sharp upon the side of the ramus, to form part of the bound- 
ary of the obturator foramen. The symphysis is the inner extremity of 
the body of the bone ; it is oval and rough, for the attachment of a liga- 
mentous structure analogous to the intervertebral substance. The ramus 
of the pubes descends obliquely outwards, and is continuous with the 
ramus of the ischium. The inner border of the ramus forms with the 
corresponding bone the arch of the pubes, and at its inferior part is con- 
siderably everted, to afford attachment to the cms penis. 

The acetabulum (cavitas cotyloidea) is a deep cup-shaped cavity, situ- 
ated at the point of union between the ilium, ischium, and pubes ; a little 
less than two-fifths being formed by the ilium, a little more than two-fifths 
by the ischium, and the remaining fifth by the pubes. It is bounded by 
a deep rim or lip, which is broad and strong above, where most resistance 
is required, and marked in front by a deep notch, which is arched over 
in the fresh subject by a strong ligament, and transmits the nutrient ves- 
sels into the joint. At the bottom of the cup and communicating with the 
notch, is a deep and circular pit (fundus acetabuli) which lodges a mass 
of fat, and gives attachment to the broad extremity of the ligamentum teres. 

The obturator or thyroid foramen is a large oval interval between the 
ischium and pubes, bounded by a narrow rough margin, to which a liga- 
mentous membrane is attached. The upper part of the foramen is increased 
in depth by the groove in the under surface of the os pubis which lodges 
the obturator vessels and nerve. 

Development. — By eight centres ; three principal, one for the ilium, one 
for the ischium, and one for the pubes ; and five secondary, one, the 
Y-shaped piece for the interval between the primitive pieces in the aceta- 
bulum, one for the crest of the ilium, one (not constant) for the anterior 
and inferior spinous process of the ilium, one for the tuberosity of the 
ischium, and one (not constant) for the angle of the os pubis. Ossification 



PELVIS. 



117 



commences in the primitive pieces, immediately after that in the vertebra?, 
firstly in the ilium, then in the ischium, and lastly in the pubes ; the first 
ossific deposits being situated near to the future acetabulum. At birth the 
acetabulum, the crest of the ilium, and the ramus of the pubes and ischium, 
are cartilaginous. The secondary centres appear at puberty, and the en- 
tire bone is not completed until the twenty-fifth year. 

Articulations. — With three bones ; sacrum, opposite innominatum, and 
femur. 

Attachments of Muscles and Ligaments. — To thirty-five muscles; to the 
ilium, thirteen ; by the outer lip of the crest, to the obliquus externus for 
two-thirds, and to the latissimus dorsi for one-third its length, and to the 
tensor vaginae femoris by its anterior fourth ; by the middle crest, to the 
internal oblique for three-fourths its length, by the remaining fourth to the 
erector spinee ; by the internal lip, to the transversalis for three-fourths, 
and to the quadratus lumborum by the posterior part of its middle third. 
By the external surface, to the gluteus medius, minimus and maximus, 
and to one head of the rectus ; by the internal surface, to the iliacus ; and 
by the anterior border to the sartorius, and the other head of the rectus. 
To the ischium, sixteen ; by its external surface, the adductor magnus and 
obturator externus ; by the internal surface, the obturator internus and 
levator ani ; by the spine, the gemellus superior, levator ani, coccygeus, 
and lesser sacro-ischiatic ligament ; by the tuberosity, the biceps, semi- 
tendinosus, semi-membranosus, gemellus inferior, quadratus femoris, erec- 
tor penis, transversus perinei, and great sacro-ischiatic ligament ; and by 
the ramus, the gracilis, accelerator urinse, and compressor urethras. To 
the os pubis, fifteen ; by its upper border, the obliquus externus, obliquus 
internus, transversalis, rectus, pyramidalis, pectineus, and psoas parvus ; 
by its external surface, the adductor longus, adductor brevis, and gracilis ; 
by its internal surface, the levator ani, compressor urethras, and obturator 
internus ; and by the ramus, the adductor magnus, and accelerator urinae. 



PELVIS. 

The pelvis considered Fig. 56* 

as a whole is divisible into 
a false and true pelvis ; 
the former is the expanded 
portion, bounded on each 
side by the ossa ilii, and 
separated from the true 
pelvis by the linea ilio-pec- 
tinea. The true pelvis is 
all that portion which is 
situated beneath the linea 
ilio-pectinea. This line 
forms the margin or brim 
of the true pelvis, while 
the included area is called 
the inlet. The form of the 
inlet is heart-shaped, ob- 
tusely pointed in front at 

* A female pelvis. 1. The last lumbar vertebrae. 2, 2. The intervertebral substance 
connecting the last lumbar vertebra with the fourth and sacrum. 3. The promontory 




118 PELVIS. 

the symphysis pubis, expanded on each side, and encroached upon be- 
hind by a projection of the upper part of the sacrum, which is named the 
promontory. The cavity is somewhat encroached upon at each side by a 
smooth quadrangular plane of bone, corresponding with the internal sur- 
face of the acetabulum, and leading to the spine of the ischium. In front 
are two fossae around the obturator foramina, for lodging the obturator 
internus muscle, at each side. The inferior termination of the pelvis is 
very irregular, and is termed the outlet. It is bounded in front by the 
convergence of the rami of the ischium and pubes, which constitute the 
arch of the pubes ; on each side by the tuberosity of the ischium, and by 
two irregular fissures formed by the greater and lesser sacro-ischiatic 
notches ; and behind by the lateral borders of the sacrum, and by the 
coccyx. 

The pelvis is placed obliquely with regard to the trunk of the body, so 
that the inner surface of the ossa pubis is directed upwards, and would 
support the superincumbent weight of the viscera. The base of the sacrum 
rises nearly four inches above the level of the upper border of the sym- 
physis pubis and the apex of the coccyx, somewhat more than half an 
inch above its low T er' border. If a line were carried through the central 
axis of the inlet, it would impinge by one extremity against the umbilicus, 
and by the other against the middle of the coccyx. The axis of the inkt 
is therefore directed downwards and backwards, while that of the outlet 
points downioards and forwards, and corresponds with a line drawn from 
the upper part of the sacrum, through the centre of the outlet. The axis 
of the cavity represents a curve, which corresponds very nearly with the 
curve of the sacrum, the extremities being indicated by the central points 
of the inlet and outlet. A knowledge of the direction of these axes is 
most important to the surgeon, as indicating the line in which instruments 
should be used in operations upon the viscera of the pelvis, and the direc- 
tion of force in the removal of calculi from the bladder ; and to the accou- 
cheur, as explaining the course taken by the fetus during parturition. 

There are certain striking differences between the male and female pel- 
vis. In the male the bones are thicker, stronger, and more solid, and the 
cavity deeper and narrower. In the female the bones are lighter and 
more delicate, the iliac fossae are large, and the ilia expanded ; the inlet, 
the outlet, and the cavity, are large, and the acetabula farther removed 
from each other ; the cavity is shallow, the tuberosities widely separated, 
the obturator foramina triangular, and the span of the pubic arch greater. 
The precise diameter of the inlet and outlet, and the depth of the cavity, 
are important considerations to the accoucheur. 

The diameters of the inlet or brim are three : 1. Antero-posterior, sacro- 
pubic or conjugate; 2. transverse; and 3. oblique. The antero-posterior 

of the sacrum. 4. The anterior surface of the sacrum, on which its transverse lines and 
foramina are seen. 5. The tip of the coccyx. 6, 6. The iliac fossee, forming the lateral 
boundaries of the false pelvis. 7. The anterior superior spinous process of the ilium; 
left side. 8. The anterior inferior spinous process. 9. The acetabulum, a. The notch 
of the acetabulum. 6. The body of the ischium, c. Its tuberosity, d. The spine of the 
ischium seen through the obturator foramen, e. The os pubis. /. The symphysis pubis. 
g. The arch of the pubes. h. The angle of the os pubis, i. The spine of the pubes ■ the 
prominent ridge between h and i is the crest of the pubes. k, k. The pectineal line of 
the pubes. /, I. The ilio-pectineal line; m, m. the prolongation of this line to the pro- 
montory of the sacrum The line represented by h, i, k, k. I, I. and m, m. is the brim of 
the true pelvis, n. The ilio-pectineal eminence, o. The smooth surface which supports 
the femoral vessels, p, p. The great sacro-ischiatic notch. 



FEMUR. 



119 



Fig. 57.* 



extends from the symphysis pubis to the middle of the promontory of the 
sacrum, and measures four inches. The transverse extends from the 
middle of the brim on one side to the same point on the opposite, and 
measures five inches. The oblique extends from the sacro- iliac symphysis 
on one side, to the margin of the brim corresponding with the acetabulum 
on the opposite, and also measures five inches. 

The diameters of the outlet are two, antero-posterior, and transverse. 
The antero-posterior diameter extends from the lower part of the symphy- 
sis pubis to the apex of the coccyx ; and the transverse, from the posterior 
part of one tuberosity to the same point on the opposite side ; they both 
measure four inches. The cavity of the pelvis measures in depth four 
inches and a half, posteriorly ; three inches and a half in the middle ; and 
one and a half at the symphysis pubis. 

Femur. — The femur, the longest bone of the skeleton, is situated ob- 
liquely in the upper part of the lower limb, articulating by means of its 
head with the acetabulum, and inclining inwards as it descends, until it 
almost meets its fellow of the opposite side at the knee. In the female 
this obliquity is greater than in the male, in consequence of the greater 
breadth of the pelvis. The femur is divisible into a shaft, a superior, 
and an inferior extremity. 

At the superior extremity is a rounded head, directed 
upwards and inwards, and marked just below its centre 
by an oval depression for the ligamentum teres. The 
head is supported by a neck, which varies in length 
and obliquity according to sex and at various periods 
of life, being long and oblique in the adult male, shorter 
and more horizontal in the female and in old age. 
Externally to the neck is a large process, the trochanter 
major, which presents upon its anterior surface an oval 
facet, for the attachment of the tendon of the gluteus 
minimus muscle ; and above, a double facet, for the 
insertion of the gluteus medius. On its posterior side 
is a vertical ridge, the linea quadrati, for the attachment 
of the quadratus femoris muscle. Upon the inner side 
of the trochanter major is a deep pit, the trochanteric or 
digital fossa, in which are inserted the tendons of the 
pyriformis, gemellus superior and inferior, and obturator 
externus and intemus muscles. Passing downwards 
from the trochanter major in front of the bone is an 
oblique ridge, which forms the inferior boundary of the 
neck, the anterior intertrochanteric line; and, behind 
another oblique ridge, the posterior intertrochanteric 
line, which terminates in a rounded tubercle upon the 
posterior and inner side of the bone, the trochanter mi- 
nor. 

The shaft of the femur is convex and rounded in 

* The right femur, seen upon the anterior aspect. 1. The shaft. 2. The head. 3. 
The neck. 4. The great trochanter. 5. The anterior intertrochanteric line 6 The 
lesser trochanter. 7. The external condyle. 8. The internal condyle. 9. The tubero- 
sity for the attachment of the external lateral ligament. 10. The fossa for the tendon 
of origin of the popliteus muscle. 11. The tuberosity for the attachment of the mterna] 
lateral ligament. 



120 



FEMUR. 



Fig. 58.' 



ai 



front, and covered with muscles ; and somewhat concave and raised into 
a rough prominent ridge behind, the linea aspera. The linea aspera near 
the upper extremity of the bone divides into three branches. The ante- 
rior branch is continued forwards in front of the lesser trochanter, and is 
continuous with the anterior intertrochanteric line ; the middle is continued 
directly upwards into the linea quadrati ; and the posterior, broad and 
strongly marked, ascends to the base of the trochanter major. Towards the 
lower extremity of the bone, the linea aspera divides into two ridges, 
which descend to the two condyles, and enclose a triangular space upon 
which rests the popliteal artery. The internal condyloid ridge is less 
marked than the external, and presents a broad and shallow groove, for 
the passage of the femoral artery. The nutritious fora- 
men is situated in or near the linea aspera, at about one- 
third from its upper extremity, and is directed obliquely 
from below upwards. 

The lower extremity of the femur is broad and por- 
ous, and divided by a smooth depression in front, and 
by a large fossa (fossa intercondyloidea) behind into 
two condyles. 

The external condyle is the broadest and most promi- 
nent, and the internal the narrowest and longest ; the 
difference in length depending upon the obliquity of the 
femur, in consequence of the separation of the two 
bones at their upper extremities by the breadth of the 
pelvis. The external condyle is marked upon its outer 
side by a prominent tuberosity, which gives attachment 
to the external lateral ligament; and immediately be- 
neath this is the fossa, which lodges the tendon of origin 
of the popliteus. By the internal surface it gives at- 
tachment to the anterior crucial ligament of the knee- 
joint ; and by its upper and posterior part, to the exter- 
nal head of the gastrocnemius and to the plantaris. The 
internal condyle projects upon its inner side into a tu- 
berosity, to which is attached the internal lateral liga-, 
ment ; above this tuberosity, at the extremity of the in- 
ternal condyloid ridge, is a tubercle, for the insertion 
of the tendon of the adductor magnus ; and beneath 
the tubercle, upon the upper surface of the condyle, a 
depression, from which the internal head of the gastrocnemius arises. 
The outer side of the internal condyle is rough and concave, for the at- 
tachment of the posterior crucial ligament. 

Development. — By jive centres ; one for the shaft, one for each extre 
mity, and one for each trochanter. The femur is the first of the long bones 
to show signs of ossification. In it, ossific matter is found immediately 
after the maxillae before the termination of the second month of embryonic 
life. The secondary deposits take place in the following order, in the 

* A diagram of the posterior aspect of the right femur, showing the lines of attach 
ment of the muscles. The muscles attached to the inner lip are, — p. the pectineus; a b, 
the adductor brevis; and a I, the adductor longus. The middle portion is occupied for 
its whole extent by a m. the adductor magnus; and is continuous superiorly with q /, 
the linea quadrati, into which the quadratus femoris is inserted. The outer lip is occu- 
pied by g m, the gluteus maximus; and b, the short head of the biceps. 



|fe" 



PATELLA — TIBIA. 121 

condyloid extremity during the last month of foetal life ;* in the head to- 
wards the end of the first year ; in the greater trochanter between the 
third and the fourth year ; ip the lesser trochanter between the thirteenth 
and fourteenth. The epiphyses and apophyses are joined to the diaphysis 
in the reverse order of their appearance, the junction commencing after 
puberty and not being completed for the condyloid epiphysis until after 
the twentieth year. 

Articulations. — With three bones ; with the os innominatum, tibia, and 
patella. 

Attachment of Muscles. — To twenty-three ; by the greater trochanter, to 
the gluteus medius and minimus, pyriformis, gemellus superior, obturator 
internus, gemellus inferior, obturator externus, and quadratus femoris ; by 
the lesser trochanter, to the common tendon of the psoas and iliacus. By 
the linea aspera, its outer lip, to the vastus externus, gluteus maximus, 
and short head of the biceps ; by its inner lip, to the vastus internus, pec- 
tineus, adductor brevis, and adductor longus ; by its middle to the ad- 
ductor magnus ; by the anterior part of the bone, to the cruraeus and 
subcruraeus ; by its condyles, to the gastrocnemius, plantaris, and 
popliteus. 

Patella. — The patella is a sesamoid bone, developed in the tendon 
of the quadriceps extensor muscle, and usually described as a bone of the 
lower extremity. It is heart-shaped in figure, the broad side being di- 
rected upwards and the apex downwards, the external surface convex, 
and the internal divided by a ridge into two smooth surfaces, to articulate 
with the condyles of the femur. The external articular surface corres- 
ponding with the external condyle is the larger of the two, and serves to 
indicate the leg to which the bone belongs. 

Development. — By a single centre, at about the middle of the third 
year. 

Articulations. — With the two condyles of the femur. 

Attachment of Muscles. — To four ; the rectus, crurseus, vastus internus, 
and vastus externus, and to the ligamentum patella?. 

Tibia. — The tibia is the inner and larger bone of the leg ; it is pris- 
moid in form, and divisible into a shaft, an upper and lower extremity. 

The upper extremity, or head, is large, and expanded on each side into 
two tuberosities. Upon their upper surface the tuberosities are smooth, to 
articulate with the condyles of the femur ; the internal articular surface 
being oval and oblong, to correspond with the internal condyle ; and the 
external broad and nearly circular. Between the two articular surfaces is 
a spinous process ; and in front and behind the spinous process a rough 
depression, giving attachment to the anterior and posterior crucial liga- 
ments. Between the two tuberosities, on the front aspect of the bone, is 
a prominent elevation, the tubercle, for the insertion of the ligamentum 
patellae, and immediately above the tubercle a smooth facet, corresponding 
with the bursa. Upon the outer side of the external tuberosity is an arti- 
cular surface, for the head of the fibula ; and upon the posterior part of 
the internal tuberosity a depression, for the insertion of the tendon of the 
semimembranosus muscle. 

* Cruveilhier remarks that this centre is so constant in the last fortnight of fcetal life, 
that it may be regarded as an important proof of the foetus having reached its full term. 



122 



FIBULA. 



Fig. 59.* 




The shaft of the tibia presents three surfaces ; internal, 
which is subcutaneous and superficial ; external, which is 
concave and marked by a sharp ridge, for the insertion 
of the interosseous membrane ; and posterior, grooved, 
for the attachment of muscles. Near the upper extremity 
of the posterior surface -is an oblique ridge, the popliteal 
line, for the attachment of the fascia of the popliteus mus 
cle ; and immediately below the oblique line, the nutritious 
canal, which is directed downwards. 

The inferior extremity of the bone is somewhat quadri- 
lateral, and prolonged on its inner side into a large process, 
the internal malleolus. Behind the internal malleolus, is 
a broad and shallow groove, for lodging the tendons of the 
tibialis posticus and flexor longus digitorum ; and farther 
outwards another groove, for the tendon of the flexor 
longus pollicis. Upon the outer side the surface is con- 
cave and triangular, rough above, for the attachment of 
the interosseous ligament ; and smooth below, to articulate 
with the fibula. Upon the extremity of the bone is a trian- 
gular smooth surface, for articulating with the astragalus. 

Development. — By three centres ; one for the shaft, and 
one for each extremity. Ossification commences in the 
tibia, immediately after the femur ; the centre for the head 
or the bone appears soon after birth, and that for the lower 
extremity during the second year ; the latter is the first 
to join the diaphysis. The bone is not complete until near the twenty- 
fifth year. Two occasional centres have sometimes been found in the ti- 
bia, one in the tubercle, the other in the internal malleolus. 

.Articulations. — With three bones ; femur, fibula, and astragalus. 
Attachment of Muscles. — To ten; by the internal tuberosity, to the sar- 
torius, gracilis, semitendinosus, and semimembranosus ; by the external 
tuberosity, to the tibialis anticus and extensor longus digitorum ; by the 
tubercle, to the ligamentum patellae ; by the external surface of the shaft, 
to the tibialis anticus ; and by the posterior surface, to the popliteus, soleus, 
flexor longus digitorum, and tibialis posticus. 

Fibula. — The fibula (irsgovr), a brooch, from its resemblance, in con- 
junction with the tibia, to the pin of an ancient brooch) is the outer and 
smaller bone of the leg; it is long and slender in figure, prismoid in shape, 
and, like other long bones, is divisible into a shaft and two extremities. 

The superior extremity or head is thick and large, and depressed upon 
the upper part by a concave surface, which articulates with the external 
tuberosity of the tibia. Externally to this surface is a thick and rough 
prominence, for the attachment of the external lateral ligament of the knee- 
joint, terminated behind by a styloid process, for the insertion of the ten- 
don of the biceps. 

The lower extremity is flattened from without inwards, and prolonged 

* The tibia and fibula of the right leg, articulated and seen from the front. 1. The 
shaft of the tibia. 2. The inner tuberosity. 3. The outer tuberosity. 4. The spinous 
process. 5. The tubercle. 6. The internal or subcutaneous surface of the shaft. 7. The 
lower extremity of the tibia. 8. The internal malleolus. 9. The shaft of the fibula. 
10. Its upper extremity. 11. Its lower extremity, the external malleolus. The sharp 
border oetween 1 and G is the crest of the tibia. 



FIBULA. 



123 



Fig. 60." 



downwards beyond the articular surface of the tibia, forming the external 
malleolus. Its external side presents a rough and triangular surface, which 
is subcutaneous. Upon the internal surface is a smooth triangular facet, 
to articulate with the astragalus; and a rough depression, for the attach- 
ment of the interosseous ligament. The anterior border is thin and sharp ; 
and the posterior, broad and grooved, for the tendons of the peronei 
muscles. 

To place the bone in its proper position, and ascertain 
to which leg it belongs, let the inferior or flattened ex- 
tremity be directed downwards, and the narrow border 
of the malleolus forwards ; the triangular subcutaneous 
surface will then point to the side corresponding with the 
limb of which the bone should form a part. 

The shaft of the fibula is prismoid, and presents three 
surfaces; external, internal, and posterior; and three 
borders. The external surface is the broadest of the 
three ; it commences upon the anterior part of the bone 
above, and curves around it so as to terminate upon its 
posterior side below. This surface is completely occu- 
pied by the two peronei muscles. The internal surface 
commences on the side of the superior articular surface, 
and terminates below, by narrowing to a ridge, which is 
continuous with the anterior border of the malleolus. It 
is marked along its middle by the interosseous ridge, 
which is lost above and below in the inner border of the 
bone. The posterior surface is twisted like the external ; 
it commences above on the posterior side of the bone, 
and terminates below on its internal side ; at about the 
middle of this surface is the nutritious foramen, which is 
directed downwards. 

The internal border commences superiorly in common 
with the interosseous ridge, and bifurcates inferiorly into 
two lines, which bound the Iriangular subcutaneous surface of the external 
malleolus. The external border begins at the base of the styloid process 
upon the head of the fibula, and winds around the bone, following the di- 
rection of the corresponding surface. The posterior border is sharp and 
prominent, and is lost inferiorly in the interosseous ridge. 

Development. — By three centres; one for the shaft, and one for each 
extremity. Ossification commences in the shaft soon after its appearance 
in the tibia ; at birth the extremities are cartilaginous, an ossific deposit 

*The tibia and fibula of the right leg articulated and seen from behind. 1. The ar- 
ticular depression for the external condyle of the femiir. 2. The articular depression 
for the internal condyle; the prominence between the two numbers is the spinous pro- 
cess. 3. The fossa and groove for the insertion of the tendon of the semimembranosus 
muscle. 4. The popliteal plane, for the support of the popliteus muscle. 5. The po- 
pliteal line. 6. The nutritious foramen. 7. The surface of the shaft upon which the 
flexor longus digitorum muscle rests. 8. The broad groove on the back part of the inner 
malleolus, for the tendons of the flexor longus digitorum and tibialis posticus. 9. The 
groove for the tendon of the flexor longus pollicis. 10. The shaft of the fibula. The 
flexor longus pollicis muscle lies upon this surface of the bone ; its superior limit being 
marked by the oblique line immediately above the number. 11. The styloid process on 
the head of the fibula for the attachment of the tendon of the biceps muscle. 12. The 
subcutaneous surface of the lower part of the shaft of the fibula. 13. The external 
malleolus formed by the lower extremity of the fibula. 14. The groove upon the pos- 
terior part of the external malleolus for the tendons of the peronei muscles. 




J 24 TARSUS — ASTRAGALUS — CALCANEUS. 

taking place in the inferior epiphysis during the second year, and in the 
superior during the -fourth or fifth. The inferior epiphysis is the first to 
become united with the diaphysis, but the bone is not completed until 
nearly the twenty-fifth year. 

Articulations. — With the tibia and astragalus. 

Attachment of Muscles. — To nine ; by the head, to the tendon of the 
biceps and soleus; by the shaft, its external surface, to the peroneus 
longus and brevis ; internal surface, to the extensor longus digitorum, 
extensor proprius pollicis, peroneus tertius, and tibialis posticus ; by the 
posterior surface, to the popliteus and flexor longus pollicis. 

Tarsus. — The bones of the tarsus are seven in number ; viz. the astra- 
galus, calcaneus, scaphoid, internal middle, and external cuneiform and 
cuboid. 

The Astragalus (os tali) may be recognised by its rounded head, a 
broad articular facet upon its convex surface, and two articular facets, 
separated by a deep groove, upon its concave surface. 

The bone is divisible into a superior and inferior surface, an external 
and internal border, and an anterior and posterior extremity. The supe- 
rior surface is convex, and presents a large quadrilateral and smooth facet 
somewhat broader in front than behind, to articulate with the tibia. The 
inferior surface is concave, and divided by a deep and rough groove (sul- 
cus tali), which lodges a strong interoessous ligament, into two facets, the 
posterior large and quadrangular, and the anterior smaller and elliptic, 
which articulate with the os calcis. The internal border is flat and irre- 
gular, and marked by a pyriform articular surface, for the inner malleolus. 
The external presents a large triangular articular facet, for the external 
malleolus, and is rough and concave in front. The anterior extremity 
presents a rounded head, surrounded by a constriction somewhat resem- 
bling a neck ; and the posterior extremity is narrow, and marked by a 
deep groove, for the tendon of the flexor longus pollicis. 

Hold the astragalus with the broad articular surface upwards, and the 
rounded head forwards ; the triangular lateral articular surface will point 
to the side to which the bone belongs.* 

Articulations. — With four bones ; tibia, fibula, calcaneus, and sca- 
phoid. 

The Calcaneus (os calcis) may be known by its large size and oblong 
figure, by the large and irregular portion which forms the heel, and by two 
articular surfaces, separated by a broad groove upon its upper side. 

The calcaneus is divisible into four surfaces, superior, interior, external, 
and internal ; and two extremities, anterior and posterior. The superior 
surface is convex behind and irregularly concave in front, where it pre- 
sents two, and sometimes three articular facets, divided by a broad and 
shallow groove (sulcus calcanei), for the interosseous ligament. The in- 
ferior surface is convex and rough, and bounded posteriorly by the two 
inferior tuberosities, of which the internal is broad and large, and the ex- 
ternal smaller and prominent. The external surface is convex and sub- 
cutaneous, and marked towards its anterior third by two grooves, often 
separated by a tubercle, for the tendons of the peroneus longus and brevis. 
The internal surface is concave and grooved, for the tendons and vessels 
which pass into the sole of the foot. At the anterior extremity of x Jiis 



SCAPHOID AND CUNEIFORM BONES. 



125 




surface is a projecting process (sustentaculum tali), 
which supports the anterior articulating surface of the 
astragalus, and serves as a pulley to the tendon of the 
flexor longus digitorum. Upon the anterior extremity 
is a flat articular surface, surmounted by a rough pro- 
jection, which affords one of the guides to the surgeon 
in the performance of Chopart's operation. The pos- 
terior extremity is prominent and convex, and consti- 
tutes the posterior tuberosity ; it is smooth for the 
upper half of its extent, where it corresponds with a 
bursa ; and rough below, for the insertion of the 
tendo A.chillis ; the lower part of this surface is bound- 
ed by the two inferior tuberosities. 

Articulations. — With tivo bones ; the astragalus 
and cuboid. In their articulated state a large oblique 
canal is situated between the astragalus and calcaneus, 
being formed by the apposition of the two grooves 
sulcus tali and calcanei. This groove is called the 
sinus tarsi, and serves to lodge a strong interosseous 
ligament which binds the two bones together. 

Attachment of Muscles. — To nine ; by the poste- 
rior tuberosity, to the tendo Achillis and plantaris ; by the inferior tube- 
rosities and under surface, to the abductor pollicis, abductor minimi 
digiti, flexor brevis digitorum, flexor accessorius, and to the plantar fascia ; 
and by the external surface, to the extensor brevis digitorum. 

The Scaphoid bone may be distinguished by its boat-like figure, con- 
cave on one side, and convex with three facets upon the other. It pre- 
sents for examination an anterior and posterior surface, a superior and 
inferior border, and two extremities, one broad, the other pointed and 
thick. The anterior surface is convex, and divided into three facets, to 
articulate with the three cuneiform bones ; and the posterior concave, to 
articulate with the rounded head of the astragalus. The superior border 
is convex and rough, and the inferior somewhat concave and irregular. 
The external extremity is broad and rough, and the internal pointed and 
prominent, so as to form a tuberosity. The external extremity sometimes 
presents a facet of articulation with the cuboid. 

If the bone be held so that the convex surface with three facets look 
forwards, and the convex border upwards, the broad extremity will point 
to the side corresponding with the foot to which the bone belongs. 

Articulations. — With four bones; astragalus and three cuneiform bones, 
sometimes also with the cuboid. 

Attachment of Muscles. — To the tendon of the tibialis posticus. 

The Internal Cuneiform may be known by its irregular wedge-shape, 
and by being larger than the two other bones bearing the same name. It 

* The dorsal surface of the left foot. 1. The astragalus; its superior quadrilateral 
articular surface. 2. The anterior extremity of the astragalus, which articulates with 
(4) the scaphoid bone. 3. The os calcis. 4. The scaphoid bone. 5. The. internal 
cuneiform bone. G. The middle cuneiform bone. 7. The external cuneiform bone. 
8. The cuboid bone. 9. The metatarsal bones of the first and second toes. 10. The 
first phalanx of the great toe. 11. The second phalanx of the great toe. 13i The first 
phalanx of the second toe. 13. Its second phalanx. 14. Its third phalanx. 
11* 



126 CUNEIFORM AND CUBOID BONES. 

presents for examination a convex and a concave surface, a long and a 
short articular border, and a small and a large extremity. 

Place the bone so that the small extremity may look upwards and the 
long articular border forwards, the concave surface will point to the side 
corresponding with the foot to which it belongs. 

The convex surface is internal and free, and assists in forming the inner 
border of the foot ; the concave is external, and in apposition with the 
middle cuneiform and second metatarsal bone ; the long border articulates 
with the metatarsal bone of the great toe, and the short border with the 
scaphoid bone. The small extremity (edge) is sharp, and the larger ex- 
tremity (base) rounded into a broad tuberosity. 

Articulations. — With four bones; scaphoid, middle cuneiform, and 
first two metatarsal bones. 

Attachment of Muscles. — To the tibialis anticus, and posticus. 

The Middle Cuneiform is the smallest of the three ; it is wedge- 
shaped, the broad extremity being placed upwards, and the sharp end 
downwards in the foot. It presents for examination four articular sur- 
faces and two extremities. The anterior and posterior surfaces have 
nothing worthy of remark. One of the lateral surfaces has a long arti- 
cular facet, extending its whole length, for the internal cuneiform ; the 
other has only a partial articular facet for the external cuneiform bone. 

If the bone be held so that the square extremity look upwards, the 
broadest side of the square being towards the holder, the small and partial 
articular surface will point to the side to which the bone belongs. 

Articulations. — With four bones ; scaphoid, internal and external 
cuneiform, and second metatarsal bone. 

Attachment of Muscles. — To the flexor brevis pollicis. 

The External Cuneiform is intermediate in size between the two 
preceding, and placed, like the middle, w r ith the broad end upwards and 
the sharp extremity downwards. It presents for examination five surfaces, 
and a superior and inferior extremity. The upper extremity is flat, of an 
oblong square form, and bevelled posteriorly, at the expense of the outer 
surface, into a sharp edge. 

If the bone be held so that the square extremity look upwards and the 
sharp border backwards, the bevelled surface will point to the side corre- 
sponding with the foot to which the bone belongs. 

Articulations. — With six bones ; scaphoid, middle cuneiform, cuboid, 
and second, third, and fourth metatarsal bones. 

Attachment of Muscles. — To the flexor brevis pollicis. 

The Cuboid Bone is irregularly cuboid in form, and marked upon its 
under surface by a deep groove, for the tendon of the peroneus longus 
muscle. It presents for examination six surfaces, three articular and 
three non-articular. The non-articular surfaces are the superior, which is 
slightly convex, and assists in forming the dorsum of the foot; the inferior, 
marked by a prominent ridge, the tuberosity, and a deep groove for the 
tendon of the peroneus longus; and an external, the smallest of the whi.e, 
and deeply notched by the commencement of the peroneal groove. The 
articular surfaces are, the posterior, which is of large size, and concavo- 
convex, to articulate with the os calcis ; anterior, of smaller size, divided 



METATARSAL BONES. 127 

by a slight ridge into two facets, for the fourth and fifth metatarsal bones ; 
and internal, a small oval articular facet, upon a large and quadrangular 
surface, for the external cuneiform bone. 

If the bone be held so that the plantar surface, with the peroneal groove, 
look downwards, and the largest articular surface backwards, the small 
non-articular surface, marked by the deep notch, will point to the side 
corresponding with the foot to which the bone belongs. 

Articulations. — With four bones; calcaneus, external cuneiform, and 
fourth and fifth metatarsal bones, sometimes also with the scaphoid. 

Attachment of Muscles. — To three; the flexor brevis pollicis, adductor 
pollicis, and flexor brevis minimi digiti. 

Upon a consideration of the articulations of the tarsus it will be ob- 
served, that each bone articulates with four adjoining bones, with the ex- 
ception of the calcaneus, which articulates with two, and the external 
cuneiform with six. 

Development. — By a single centre for each bone, with the exception of 
the os calcis, which has an epiphysis for its posterior tuberosity. The 
centres appear in the following order : calcanean, sixth month ; astra- 
galan, seventh month ; . cuboid, tenth month ; external cuneiform, during 
the first year ; internal cuneiform, during the third year ; middle cunei- 
form and scaphoid, during the fourth year. The epiphysis of the calca- 
neus appears at the ninth year, and is united with the diaphysis at about 
the fifteenth. 

The Metatarsal Bones, Jive in number, are long bones, and divisible 
therefore into a shaft and two extremities. The shaft is prismoid, and 
compressed from side to side ; the posterior extremity, or base, is square- 
shaped, to articulate with the tarsal bones, and with each other ; and the 
anterior extremity presents a rounded head, circumscribed by a neck, to 
articulate with the first row of phalanges. 

Peculiar Metatarsal Bones. — The first is shorter and larger than the 
rest, and forms part of the inner border of the foot ; its posterior extremity 
presents only one lateral articular surface, and an oval rough prominence 
beneath, for the insertion of the tendon of the peroneus longus. The 
anterior extremity has, upon its plantar surface, two grooved facets, for 
sesamoid bones. 

The second is the longest and largest of the remaining metatarsal bones ; 
it presents at its base three articular facets, for the three cuneiform bones ; 
a large oval facet, but often no articular surface, on its inner side, to arti- 
culate with the metatarsal bone of the great toe, and two externally for 
the third metatarsal bone. 

The third may be known by two facets upon the outer side of its base, 
corresponding with the second, and may be distinguished by its smaller 
size. 

The fourth may be distinguished by its smaller size, and by having a 
single articular surface on each side of the base. 

The fifth is recognised by its broad baseband by its large tuberosity in 
place of an articular surface upon its outer side. 

Development. — Each bone by two centres ; one for the body and one 
for the digital extremity in the four outer metatarsal bones ; and one for 
the body, the other for the base in the metatarsal bone of the great toe. 
Ossific deposition appears in these bones at the same time with the verte- 



128 



PHALANGES. 




Fia 62.* bree ; the epiphyses, commencing with the great toe 

and proceeding to the fifth, appear towards the close 
of the second year, consolidation being effected at 
eighteen. 

Articulations. — With the tarsal bones by one ex- 
tremity, and with the first row of phalanges by the 
other. The number of tarsal bones with which each 
metatarsal articulates from within outwards, is the 
same as between the metacarpus and carpus, one for 
the first, three for the second, one for the third, two 
for the fourth, and one for the fifth, forming the cipher 
13121. 

Attachment of Muscles. — To fourteen ; to the first, 
the peroneus longus and first dorsal interosseous 
muscle ; to the second, two dorsal interossei and 
transversus pedis ; to the third, two dorsal and one 
plantar interosseous, adductor pollicis and transversus 
pedis; to the fourth, two dorsal and one plantar 
interosseous, adductor pollicis and transversus pedis ; 
to the fifth, one dorsal and one plantar interosseous, 
peroneus brevis, peroneus tertius, abductor minimi 
digiti, flexor brevis minimi digiti, and transversus pedis. 

Phalanges.— There are two phalanges in the great toe, and three in 
the other toes, as in the hand. They are long bones, divisible into a 
central portion and extremities. 

The phalanges of the first row are convex above, concave upon the 
under surface, and compressed from side to side. The posterior extre- 
mity has a single concave articular surface, for the head of the metatarsal 
bone ; and the anterior extremity, a pulley-like surface for the second 
phalanx. 

The second phalanges are short and diminutive, but somewhat broader 
than those of the first row. 

The third, or ungual phalanges, including the second phalanx of the 
great toe, are flattened from above downwards, spread out laterally at the 
base, to articulate with the second row, and at the opposite extremity, to 
support the nail and the rounded extremity of the toe. 

Development. — By two centres ; one for the body and one for the meta- 
carpal extremity. Ossification commences in these bones after that in the 
metatarsus, appearing first in the last phalanges, then in the first, and last 
of all in the middle row. The bones are completed at eighteen. 

Articulations. — The first row with the metatarsal bones and second 
phalanges ; the second, of the great toe with the first phalanx, and of the 

* The sole of the left -foot. 1. The inner tuberosity of the os calcis. 2. The outer 
tuberosity. 3. The groove for the tendon of the flexor longus digitorum ; this figure 
indicates also the sustentaculum tali. 4. The rounded head of the astragalus. 5. Tlue 
scaphoid bone. C. Its tuberosity, 7. The internal cuneiform bone; its broad extremity 
8. The middle cuneiform bone. 9. The external cuneiform bone. 10, 11. The cuboid 
bone. 11. Refers to the groove for the tendon of the peroneus longus : the prominence 
between this groove and figure 10 is the tuberosity. 12, 12. The metatarsal bones. 
13, 1 •'{. The first phalanges. 14, 14. The second phalanges of the four lesser toes. 
10, 15. The third, or ungual phalanges of the four lesser toes. 10. The last phalanx 
of the great toe. 



SESAMOID BONES. 129 

other toes with the first and third phalanges ; and the third, with the se- 
cond row. 

Attachment of Muscles. — To twenty-three ; to the first phalanges; great 
toe, the innermost tendon of the extensor brevis digitorum, abductor pol- 
licis, adductor pollicis, flexor brevis pollicis, and transversus pedis ; second 
toe, first dorsal and first palmar interosseous and lumbricalis ; third toe, 
second dorsal and second palmar interosseous and lumbricalis ; fourth toe, 
third dorsal and third palmar interosseous and lumbricalis ; fifth toe, 
fourth dorsal interosseous, abductor minimi digiti, flexor brevis minimi 
digiti and lumbricalis. Second phalanges ; great toe, extensor longus pol- 
licis, and flexor longus pollicis ; other toes, one slip of the common tendon 
of the extensor longus and extensor brevis digitorum, and flexor brevis 
digitorum. Third phalanges; two slips of the common tendon of the 
extensor longus and extensor brevis digitorum, and the flexor longus digi- 
torum. 

Sesamoid Bones. — These are small osseous masses, developed in those 
tendons which exert a certain degree of force upon the surface over which 
they glide, or where, by continued pressure and friction, the tendon would 
become a source of irritation to neighbouring parts, as to joints. The 
best example of a sesamoid bone is the patella, developed in the common 
tendon of the quadriceps extensor, and resting upon the front of the knee- 
joint. Besides the patella, there are four pairs of sesamoid bones included 
in the number of pieces which compose the skeleton, two upon the meta- 
carpophalangeal articulation of each thumb, and existing in the tendons 
of insertion of the flexor brevis pollicis, and two upon the corresponding 
joint in the foot, in the tendons of the muscles inserted into the base of 
the first phalanx. In addition to these, there is often a sesamoid bone 
upon the metacarpophalangeal joint of the little finger ; and upon the 
corresponding joint in the foot, in the tendons inserted into the base of 
the first phalanx ; there is one also in the tendon of the peroneus longus 
muscle, where it glides through the groove in the cuboid bone ; sometimes 
in the tendons, as they wind around the inner and outer malleolus ; in the 
psoas and iliacus, where they glide over the body of the os pubis ; and in 
the external head of the gastrocnemius. 

The bones of the tympanum, as they belong to the apparatus of hearing, 
will be described with the anatomy of the ear. 



CHAPTER III. 

ON THE LIGAMENTS. 



The bones are variously connected with each other in the construction 
of the skeleton, and the connexion between any two bones constitutes a 
joint or articulation. If the joint be immovable, the surfaces of the bones 
are applied in direct contact ; but if motion be intended, the opposing 
surfaces are expanded, and coated by an elastic substance, named carti- 
lage ; a fluid secreted by a membrane closed on all sides lubricates their 

i 



130 ARTICULATIONS. 

surface, and they are firmly held together by means of short bands of 
glistening fibres, which are called ligaments (ligare, to bind). The study 
of the ligaments is named syndesmology (rfuv together, 5s<r^bs bond), which, 
with the anatomy of the articulations, forms the subject of the present 
chapter. 

The forms of articulation met with in the human frame may be consi- 
dered under three classes : Synarthrosis, Amphi-arthrosis, and Diarthrosis. 

Synarthrosis ( tfuv, agdf>uais articulation) is expressive of the fixed form 
of joint in which the bones are immovably connected with each other. 
The kinds of synarthrosis are four in number. 1. Sutura. 2. Harmonia. 
3. Schindylesis. 4. Gomphosis. The characters of the three first have 
been sufficiently explained in the preceding chapter, p. 83. It is here 
only necessary to state that, in the construction of sutures, the substance 
of the bones is not in immediate contact, but is separated by a layer of 
membrane which is continuous externally with the pericranium and inter- 
nally with the dura mater. It is the latter connexion which gives rise to 
the great difficulty sometimes experienced in tearing the calvarium from 
the dura mater. Cruveilhier describes this interposed membrane as the 
sutural cartilage ; I never saw any structure in the sutures which could 
be regarded as cartilage, and the history of the formation of the cranial 
bones would seem to point to a different explanation. The fourth, Gom- 
phosis (yo/x<po?, a nail), is expressive of the insertion of one bone into 
another, in the same manner that a nail is fixed into a board ; this is il- 
lustrated in the articulation of the teeth w T ith the alveoli of the maxillary 
bones. 

Amphi-arthrosis (ajxqji both, ag^wtfig) is a joint intermediate in aptitude 
for motion between the immovable synarthrosis and the movable diarthro- 
sis. It is constituted by the approximation of surfaces partly coated with 
cartilage lined by synovial membrane, and partly connected by interosse- 
ous ligaments, or by the intervention of an elastic fibro-cartilage which 
adheres to the ends of both bones. Examples of this articulation are seen 
in the union between the bodies of the vertebrae, of the sacrum with the 
coccyx, of the pieces of the sternum, the sacro-iliac and pubic symphyses 
(<rOv, (pusiv, to grow together), and according to some, of the necks of the 
ribs with the transverse processes. 

Diarthrosis (&a through, ag6gu(fts) is a movable articulation, which 
constitutes by far the greater number of the joints of the body. The de- 
gree of motion in this class has given rise to a subdivision into three genera, 
Arthrodia, Ginglymus, and Enarthrosis. 

Arthrodia is the movable joint in which the extent of motion is slight 
and limited, as in the articulation of the clavicle, of the ribs, articular pro- 
cesses of the vertebrae, axis with the atlas, radius with the ulna, fibula 
with the tibia, carpal and metacarpal, tarsal and metatarsal bones. 

Ginglymus (7177X0^0?, a hinge), or hinge-joint, is the movement of 
bones upon each other in two directions only, viz. forwards and back- 
wards ; but the degree of motion may be very considerable. The instances 
of this form of joint are numerous ; they comprehend the elbow, wrist, 
metacarpo-phalangeal and phalangeal joints in the upper extremity ; and 
the knee, ankle, metatarso-phalangeal and phalangeal joints in the lower 
extremity. The lower jaw may also be admitted into this category, as 
partaking more of the character of the hinge-joint than the less movable 
arthrodia. 



Synarthrosis. 



MOVEMENTS OF JOINTS. 131 

The form of the ginglymoid joint is somewhat quadrilateral, and each 
of its four sides is provided with a ligament, which is named from its posi- 
tion, anterior, posterior, internal, or external lateral. The lateral liga- 
ments are thick and strong, and are the chief bond of union between the 
bones. The antenor and posterior are thin and loose, in order to permit 
the required extent of movement. 

Enarthrosis (sv in, ol$£u«ic) is the most extensive in its range of motion 
of all the movable joints. From the manner of connexion and form of 
the bones in this articulation, it is called the ball-and-socket-joint. There 
are two instances in the body, viz. the hip and the shoulder. 

I have been in the habit of adding to the preceding the carpo-metacar- 
pal articulation of the thumb, although not strictly a ball-and-socket-joint, 
from the great extent of motion which it enjoys, and from the nature of the 
ligament connecting the bones. As far as the articular surfaces are con- 
cerned, it is rather a double than a single ball-and-socket, and the whole 
of these considerations remove it from the simple arthrodial and ginglymoid 
groups. 

The ball-and-socket joint has a circular form ; and in place of the four 
distinct ligaments of the ginglymus, is enclosed in a bag of ligamentous 
membrane, called a capsular ligament. 

The kinds of articulation may probably be conveyed in a more satis- 
factory manner in the tabular form, thus : 

Sutura - - • - - bones of the skull. 
Harmonia - - - superior maxillary bones. 
Schindylesis - - vomer with rostrum. 
Gomphosis - - - teeth with alveoli. 
A mphi- arthrosis - Bodies of the vertebrae - Symphyses. 

C Arthrodia - - - carpal and tarsal bones. 
Diarthrosis. < Ginglymus - - - elbow, wrist, knee, ankle. 
( Enarthrosis - - - hip, shoulder. 

The motions permitted in joints may be referred to four heads, viz. 1. 
Gliding. 2. Angular movement. 3. Circumduction. 4. Rotation. 

1. Gliding is the simple movement of one articular surface upon an- 
other, and exists to a greater or less extent in all the joints. In the least 
movable joints, as in the carpus and tarsus, this is the only motion which is 
permitted. 

2. Angular movement may be performed in four different directions, 
either forwards and backwards, as in flexion and extension ; or inwards 
and outwards, constituting adduction and abduction. Flexion and exten- 
sion are illustrated in the ginglymoid joint, and exist in a large proportion 
of the joints of the body. Adduction and abduction conjoined with flexion 
and extension, are met with complete, only in the most movable joints, 
as in the shoulder, the hip, and the thumb. In the wrist and in the ankle 
adduction and abduction are only partial. 

3. Circumduction is most strikingly exhibited in the shoulder and hip- 
joints'; it consists in the slight degree of motion which takes place in the 
head of a bone against its articular cavity, while the extremity of the limb 
is made to describe a large circle upon a plane surface. It is also seen, 
but in a less degree, in the carpo-metacarpal articulation of the thumb, 
.netacarpo-phalangeal articulations of the fingers and toes, and in the 
elbow when that joint is flexed and the end of the humerus fixed. 



132 STRUCTURE OF CARTILAGE. 

4. Rotation is the movement of a bone upon its own axis, and is illus- 
trated in the hip and shoulder, or better in the rotation of the cup of the 
radius against the eminentia capitata of the humerus. Rotation is also 
observed in the movements of the atlas upon the axis, in which the odon- 
toid process serves as a pivot around which the atlas turns. 

The structures entering into the composition of a joint are bone, carti- 
lage, fibrous tissue, adipose tissue, and synovial membrane. Cartilage 
forms a thin coating to the articular extremities of bones, sometimes pre- 
senting a smooth surface which moves on a corresponding smooth surface 
of the articulating bone ; sometimes forming a plate smooth on both sur- 
faces and interposed between the cartilaginous ends of two bones, inter- 
articular ; and sometimes acting as the connecting medium between bones 
without any free surface, interosseous. Fibrous tissue enters into the con- 
struction of joints under the form of ligament, in one situation constituting 
bands of various breadth and thickness, in another a layer which extends 
completely around the joint, and is then called a capsular ligament. All 
the ligaments of joints are composed of that variety of fibrous tissue term- 
ed white fibrous tissue, but in some situations ligaments are found which 
consist of yellow fibrous tissue, for example, the ligamenta subflava of the 
arches of the vertebral column. Adipose tissue exists in variable quantity 
in relation with joints, where it performs, among other offices, that of a 
valve or spring, which occupies any vacant space that may be formed 
during the movements of the joint, and effectually prevents the occurrence 
of a vacuum in those cavities. This purpose pf adipose tissue is exempli- 
fied in the cushion of fat at the bottom of the acetabulum, and in the 
similar cushion behind the ligamentum patellae. Synovial membrane 
constitutes the beautiful smooth and polished lining of a joint, and con- 
tains the fluid termed synovia, by means of which the adapted surfaces 
are enabled to move upon each other with the perfect ease and freedom 
which are known to exist. 

Cartilage. — In the structure of joints, cartilage serves the double pur- 
pose of a connecting and separating medium. In the former capacity 
possessing great strength, and in the latter smoothness and elasticity. In 

Fig. 63 * Fig.. 64.f 




i<> 



8^ 




0° 

6b 



* A portion of articular cartilage from the head of the fibula, showing the appearance 
and arrangement of the cells near to the bone. The section is made vertically to the 
surface, and magnified 155 diameters. The irregular line to the right is the bo»*^ary 
of the bone. 

t A view of the same section, at about midway between the bone and the free sur- 
face. 



STRUCTURE OF CARTILAGE. 



133 



Fig. 65* 




reference to its intimate structure it admits of classification into three 
kinds, — true cartilage, reticular cartilage, and fibrous cartilage. 

True Cartilage is composed of a semi-transparent homo- 
geneous substance (hyaline or vitreous substance) contain- 
ing a number of minute cells (cartilage corpuscles) dispersed 
at short intervals through its structure. The cells are oval, 
oblong, or polyhedral in shape, and more or less flattened ; 
their membranous envelope is blended with the intercellular 
substance, and they contain in their interior secondary cells, 
nuclei, nucleoli, oil-globules, and more or less of granular 
matter. Cartilage cells have an average measurement of 
75*53 of an inch in their long diameter ; they are sometimes 
isolated, sometimes grouped in pairs, and sometimes dis- 
posed in a linear group of three or four. They are larger 
near the bone than at the surface, and in the latter situation 
are long and slender in form, and arranged in rows having their long axis 
parallel with the plane of the surface. True cartilage is pearl-white or 
bluish and opaline in colour, and its intercellular substance is semitrans- 
parent and structureless. These characters, however, are changed when 
it exhibits a tendency to ossify. In the latter case the intercellular sub- 
stance becomes fibrous and more or less opaque, its colour is yellowish, 
and the cells are found to contain a greater number of oil-globules than 
in its natural state. 

The true cartilages are, the articular, costal, ensiform, thyroid, cricoid, 
arytenoid, tracheal and bronchial, nasal, meatus auris, the pulley of the 
trochlearis muscle, and temporary cartilage or the cartilage of bone pre- 
viously to ossification. f 

Reticular cartilage is composed of cells (VsStj of an inch in diameter), 
separated from each other by an opaque, subfibrous, intercellular network, 
the breadth of the cells being considerably greater than that of the inter- 
cellular structure. The cells are parent cells, containing others of second- 
ary formation, together with nuclei, nucleoli, granular matter, and oil- 
globules in greater number than those of true cartilage. The fibres are 
short, imperfect, loose in texture, and yellowish. The instances of reti- 
cular cartilage are, the pinna, epiglottis, and Eustachian tube. 



Fig. 66.* 



Fig. C7.§ 





*A portion of articular cartilage near the synovial surface of an articulation; the line 
to the left is that of the synovial boundary. 
t Page 47. 

t A portion of, reticular cartilage. The section is taken from the pinna, and magni- 
fied 155 diameters. 

§ A portion of fibrous cartilage. The section is taken from the symphysis pubis, and 
magnified 155 diameters. 

12 



134 



WHITE FIBROUS TISSUE. 



Fibrous cartilage is composed of a network of white glistening fibres, 
collected into fasciculi of various size, and containing in its meshes cells 
and a subfibrous tissue resembling that of reticular cartilage. The fibres 
of fibrous cartilages are identical with those of fibrous tissue, the cells are 
large (about yoWh °f an mcn ) as m reticular cartilage, and the areolae 
are variable in dimensions. It is this latter character that constitutes the 
difference between different fibrous cartilages, some being composed al- 
most entirely of fibres with few and small interstices, as the interarticular 
cartilages, while others exhibit large spaces filled with an imperfect fibrous 
tissue and cells, as the intervertebral substance. 

The fibrous cartilages admit of arrangement into four groups, namely, 
interarticular, stratiform, interosseous, and free. The instances of inter- 
articular Jib rous cartilages (menisci) are those of the lower jaw, sternal 
and acromial end of the clavicle, wrist, carpus, knee, to which may be 
added the fibrous cartilages of circumference, glenoid and cotyloid. The 
stratiform, fibrous cartilages are such as form a thin coating to the grooves 
on bone through which tendons play. The interosseous fibrous cartilages 
are the intervertebral substance and symphysis pubis. The free fibrous 
cartilages are the tarsal cartilages of the eyelids. 

The develojyment of cartilage is the same with that of cartilage of bone 
(page 46), the different forms of cartilage resulting from subsequent changes 
in the intercellular substance and cells. Thus, for example, in articular 
cartilage the cells undergo the lowest degree of development, are very 
disproportionate to the intercellular substance, and the latter remains per 
manently structureless. In reticular cartilage the cells possess a more 
active growth, and surpass in bulk the intercellular substance, while the 
latter is composed also of cells, which assume a fibrous disposition. In 
fibrous cartilage development is most energetic in the intercellular sub- 
stance ; this is converted into fasciculi of fibrous tissue, while the inter- 
spaces are filled with cells and imperfect fibrous tissue in every stage of 
development. 

Fibrous Tissue is one of the most generally dis- 
tributed of all the animal tissues ; it is composed 
of fibres of extreme minuteness, and presents itself 
under three elementary forms ; namely, white fibrous 
tissue, yellow fibrous tissue, and red fibrous tissue. 
In white fibrous tissue the fibres are cylindrical, 
exceedingly minute, (about yi^oo of an inch in di- 
ameter), transparent and undulating ; they are col- 
lected into small fasciculi (from 3^^ to yo^os °^ 
an inch) and these latter form larger fasciculi, which 
according to their arrangement give rise to the pro- 
duction of thin laminae, membranes, ligamentous 
bands, and tendinous cords. The connecting me- 
dium of the fibres in the formation of the primitive 
fasciculi is a transparent structureless interfibrous 
substance or blastema, to which in most situations 
are added numerous minute dark filaments derived 
from nuclei and thence termed nuclear filaments. 

* White fibrous tissue: — 2. Straight appearance of the tissue when stretched. 1, 3, 
4, 5. Various wavy appearances which the tissue exhibits when not stretched. — Magni- 
fied 320 diameters. 



Fig. 68. 




YELLOW FIBROUS TISSUE. 135 

The nuclear filaments are sometimes wound spirally around the fasciculi 
or interlace with their separate fibres, at other times they are variously 
twisted and run parallel with the fasciculi. The fasciculi are connected 
and held together in the formation of membranes and cords by loose fibres 
which are interwoven between them, or by mutual interlacement. 

Examples of white fibrous tissue are met with in three principal forms, 
namely, membrane, ligament, and tendon. 

The membranous form of white fibrous tissue is seen in the common 
connecting medium of the body, namely, fibro-cellular or areolar tissue, 
in which the membrane is extremely thin and disposed in laminae, bands, 
or threads, leaving interstices of various size between them. It is seen 
also in the condensed covering of various organs, as the periosteum, peri- 
chondrium, capsulae propriae of glands, membranes of the brain, sclerotic 
coat of the eyeball, pericardium, fasciae ; sheaths of muscles, tendons, 
vessels, nerves, and ducts ; sheaths of the erectile organs, and the corium 
of the dermic and mucous membrane. 

Ligament is the name given to those bands of various breadth and thick- 
ness which retain the articular ends of bones in contact in the construction 
of joints. They are glistening and inelastic, and composed of fasciculi 
of fibrous tissue ranged in a parallel direction side by side, or in some 
situations interwoven with each other. The fasciculi are held together 
by separate fibres, or by areolar tissue. 

Tendon is the collection of parallel fasciculi of fibrous tissue, by means 
of which muscles are attached to bones. They are constructed on the 
same principle with ligaments, are usually rounded in their figure, but in 
some instances are spread out so as to assume a membranous form. In 
the latter state they are called aponeuroses. 

Yellow fibrous tissue is known also by the appellation Fi s- 69 * 
elastic tissue, from one of its more prominent physical pro- 
perties, a property which permits of its fibres being drawn 
out to double their length, and again returning to their 
original dimensions. The fibres of elastic tissue are trans- 
parent, brittle, flat or polyhedral in shape, colourless when 
single, but yellowish in an aggregated form, and considera- , 
bly thicker (50W of an inch in diameter) than the fibres 
of white fibrous tissue. In the construction of their pecu- 
liar tissue they communicate with each other by means of 
short oblique fibres, which unite with adjoining fibres at 
acute or obtuse angles, without any enlargement of the 
fibre with which they are joined. This circumstance has 
given rise to the idea of these fibres giving off branches, 
an expression derived from the division of blood-vessels, 
and another term borrowed from the same source has been 
applied to their communication with each other, namely, 
inosculation ; but both these expressions in their literal meaning are incor- 
rect. When yellow fibrous tissue is cut or torn, the fibres in consequence 
of their elasticity become clubbed and curved at the extremity, a striking 
character of this tissue. 

* Yellow fibrous tissue, showing the curly and branched disposition of its fibrillse, 
their definite outline, and abrupt mode of fracture. At 1, the structure "is not disturbed, 
as in the rest of the specimen. Magnified 320 diameters. 




136 ADIPOSE TISSUE. 

The instances of yellow fibrous tissue are : the ligamenta subflava of 
the arches of the vertebrae, cordse vocales, thyro-epiglottic ligament, crico- 
thyroidean membrane, the membranous layers connecting the cartilaginous 
rings of the trachea and bronchial tubes, the capsula propria of the spleen 
and the middle coat of arteries. It is also met with around some parts of 
the alimentary canal, as the oesophagus, cardia, and anus, around the male 
and female urethra, in the fascia lata, and in the corium of the skin. 

Red fibrous tissue is also termed contractile tissue, from a peculiar pro- 
perty which it possesses, and which places it physiologically in an inter- 
mediate position between white fibrous tissue and muscular fibre. Its 
fibres are cylindrical, transparent, reddish in hue, and collected into fasci- 
culi. It is met with in the corium of the skin, in the dartos, around the 
nipple, in the excretory ducts of glands, in the coats of blood-vessels, 
particularly veins, in the iris, in the intervascular spaces of the erectile 
tissue of the penis and clitoris, around the urethra, and around the vagina. 

Adipose Tissue is composed of minute cells, 
Fig. 70.* aggregated together in clusters of various size 

within the areolae of fibro-cellular tissue. The 
cells of adipose tissue are identical in manner of 
formation with other cells, being developed on 
nuclei and increasing in size by the formation of 
fluid in their interior. In adipose cells this fluid, 
instead of being albuminous as in other cells, is 
oleaginous, the oil at first appearing in separate 
globules, which subsequently coalesce into a sin- 
gle drop. The size of adipose cells at their full 
development is about 7 -jjq of an inch in diameter ; 
when isolated they are globular in form, but are 
hexagonal or polyhedral when compressed. They are perfectly transparent, 
the cell-membrane being structureless and their nucleus disappearing as 
they attain their full size. 

Synovial Membrane is a thin membranous layer, which invests the 
articular cartilages of the bones, and is thence reflected upon the surfaces 
of the ligaments which surround and enter into the composition of a joint. 
It resembles the serous membranes in being a shut sac, and secretes a 
transparent and viscous fluid, which is named synovia. Synovia is an 
alkaline secretion, containing albumen, which is coagulable at a boiling 
temperature. The continuation of this membrane over the surface of the 
articular cartilage, a much-agitated question, has been decided by the in- 
teresting discoveries of Henle, who has ascertained the existence of an 
epithelium upon cartilage identical with that produced by the reflected 
portion of the membrane. In some of the joints the synovial membrane 
is pressed into the articular cavity by a cushion of fat : this mass was called 
by Havers the synovial gland, from an incorrect supposition that it was 
the source of the synovia ; it is found in the hip and in the knee-joint. 
In the knee-joint, moreover, the synovial membrane forms folds, which 
are most improperly named ligaments, as the mucous and alar ligaments, 
the two latter being an appendage to the cushion of fat. Besides the 

* Fat vesicles, assuming the polyhedral form from pressure against one another. The 
capillary vessels are not represented. From the omentum : magnified about 300 dia- 
meters. 




LIGAMENTS OF THE TRUNK. 



137 



synovial membranes entering into the composi- 
tion of joints, there are numerous smaller sacs 
of a similar kind interposed between surfaces 
which move upon each other so as to cause 
friction ; they are often associated with the arti- 
culations. These are the bursa mucosae, ; they 
are shut sacs, analogous in structure to synovial 
membranes, and secreting a similar synovial 
fluid. 

The epithelium of synovial membranes is of 
the kind termed tessellated ; it is developed in 
the same manner with the epithelium of other 
free surfaces, and is continually reproduced 
from beneath, while the superficial layers are 
being rubbed off and lost. 



Fig. 71 * 




ARTICULATIONS 



The joints may be arranged, according to a natural division, into those 
of the trunk, those of the upper extremity, and those of the lower 
extremity. 



Ligaments of the Trunk.- 
into ten groups, viz. — 



-The articulations of the trunk are divisible 



1. Of the vertebral column. 

2. Of the atlas, with the occipital bone. 

3. Of the axis, with the occipital bone. 

4. Of the atlas, with the axis. 

5. Of the lower jaw. 

6. Of the ribs, with the vertebrae. 

7. Of the ribs, with the sternum, and with each other. 

8. Of the sternum. 

9. Of the vertebral column, with the pelvis. 
10. Of the pelvis. 

1. Articulation of the Vertebral Column. — The ligaments connecting 
together the different pieces of the vertebral column, admit of the same 
arrangement with that of the vertebrae themselves. Thus the ligaments 

Of the bodies are the — 



Anterior common ligament, 
Posterior common ligament, 
Intervertebral substance. 
Ligamenta subflava. 
Capsular ligaments, 
Synovial membranes. 
Inter-spinous, 
Supra-spinous. 
Of the transverse processes, — Inter-transverse. 



Of the arches, — 

Of the articular processes, — 

Of the spinous processes, — 



* Epithelium of serous membrane: — At a, an accidental fold is represented, the two 
dark edges of which exhibit the thickness of the particles, and of their nuclei, b. One 
of the oval nuclei, c. Line of junction between two particles. Magnified 300 dia- 
meters. 

12* 



138 



LIGAMENTS OF THE VERTEBRAL COLUMN. 



Fig. 72.* 




Fig. 73.f 



Bodies. — The Anterior common ligament is a broad and riband-like 
band of ligamentous fibres, extending along the front surface of the verte- 
bral column, from the axis to the sacrum. It is intimately connected 

with the intervertebral substances, and 
less closely with the bodies of the ver- 
tebrae. In the dorsal region it is thicker 
than in the cervical and lumbar, and 
consists of a median and two lateral 
portions, separated from each other by a 
series of openings for the passage of 
vessels. The ligament is composed of 
fibres of various length closely inter- 
woven with each other ; the deeper and 
shorter crossing the intervertebral sub- 
stances from one vertebra to the next ; 
and the superficial and longer fibres crossing three or four vertebrae. 

The anterior common ligament is in relation by its posterior or vertebral 
surface, with the intervertebral substances, the bodies of the vertebrae, and 
with the vessels, principally veins, which separate its central from its 
lateral portions. By its anterior or visceral surface it is 
in relation in the neck, with the longus colli muscles, the 
pharynx and the oesophagus ; in the thoracic region, 
with the aorta, the venae azygos, and thoracic duct ; and 
in the lumbar region with the aorta, right renal artery, 
right lumbar arteries, arteria sacra media, vena cava in- 
ferior, left lumbar veins, receptaculum chyli, the com- 
mencement of the thoracic duct, and the tendons of the 
lesser muscle of the diaphragm with the fibres of which 
the ligamentous fibres interlace. 

The Posterior common ligament lies upon the posterior 
surface of the bodies of the vertebrae, and extends from 
the axis to the sacrum. It is broad opposite the inter- 
vertebral substances, to which it is closely adherent ; and 
narrow and thick over the bodies of the vertebrae, from 
which it is separated by the veins of the base of the ver- 
tebrae. It is composed like the anterior ligament of shorter and longer 
fibres which are disposed in a similar manner. 

The posterior common ligament is in relation by its anterior surface 
with the intervertebral substances, the bodies of the vertebrae, and with 
the venae basum vertebrarum ; and by its posterior surface with the dura 
mater of the spinal cord, some loose areolar tissue and numerous small 
veins being interposed. 

The intervertebral substance is a lenticular disc of fibrous cartilage, 

*The anterior ligaments of the vertebra?, and ligaments of the ribs. 1. The anterior 
common ligament. 2. The anterior costo-vertebral or stellate ligament. 3. The ante-, 
nor costo-transverse ligament. 4. The interarticular ligament connecting the head of 
the rib to the intervertebral substance, and separating the two synovial membranes of 
this articulation. 

f A posterior view of the bodies of three dorsal vertebra?, connected by their interver- 
tebral substance 1, 1. The lamina? (2) have been sawn through near the bodies of the 
vertebra 3 , and the arches and processes removed, in order to show (3) the posterior 
common ligament. A part of one of the openings in the posterior surface of the ver- 
tebra?, for the transmission of the vena basis vertebra?, is seen at 4, by the side of the 
narrow and unattached portion of the ligament. 




LIGAMENTS OF THE VERTEBRAL COLUMN. 139 

interposed between each of the vertebrae from the axis to the sacrum, and 
retaining them firmly in connexion with each other. It differs in thick- 
ness in different parts of the column, and varies in depth at different points 
of its extent ; thus, it is thickest in the lumbar region, deepest in front in 
the cervical and lumbar regions, and behind in the dorsal region ; and 
contributes, in a great measure, to the formation of the natural curves of 
the vertebral column. 

When the intervertebral substance is bisected either horizontally or 
vertically, it is seen to be composed of a series of layers of dense fibrous 
tissue, separated by interstices filled with the softer kind. The central 
part of each intervertebral disc is wholly made up of this softer fibrous 
cartilage, which has the appearance of a pulp, and is so elastic as to rise 
above the level of the section as soon as its division is completed. When 
examined from the front, the layers are found to consist of fibres passing 
obliquely between the two vertebrae, in one layer passing from left to 
right, in the next from right to left, alternating in each successive layer. 

Arches. — The ligamenta subflava are two 
thin planes, of yellow fibrous tissue, situated be- 
tween the arches of each pair of vertebras, from 
the axis to the sacrum. From the imbricated 
position of the laminae they are attached to the 
posterior surface of the vertebra below r , and to 
the anterior surface of the arch of the vertebra 
above, and are separated from each other at the 
middle line by a slight interspace. They coun- 
teract by their elasticity, the efforts of the flexor 
muscles of the trunk ; and by preserving the 
upright position of the spine, limit the expendi- 
ture of muscular force. They are longer in the 
cervical than in the other regions of the spine, and are thickest in the 
lumbar region. 

The ligamenta subflava are in relation by both surfaces with the 
meningo-rachidian veins, and internally they are separated from the dura 
mater of the spinal cord by those veins and some loose areolar and adipose 
tissue. 

Articular Processes. — The ligaments of the articular processes of the 
vertebrae are loose synovial capsules which surround the articulating sur- 
faces. They are protected on their external side by a thin layer of liga- 
mentous fibres. 

Spinous Processes. — The inter-spinous ligaments are thin and mem- 
branous, and are extended between the spinous processes in the dorsal 
and lumbar regions. They are thickest in the latter region ; and are in 
relation with the multifidus spinas muscle at each side. 

The Supraspinous ligament (fig. 82) is a strong and inelastic fibrous 
cord, which extends from the apex of the spinous process of the last cer- 
vical vertebra to the sacrum, being attached to each spinous process in its 
course ; it is thickest in the lumbar region. The continuation of this li^a- 
ment upwards to the tuberosity of the occipital bone, constitutes the rudi- 
mentary ligamentum nuchas of man. The latter is strengthened, as in 

* An internal view of the arches of three vertebrae. To obtain this view the laminae 
have been divided through their pedicles. 1. One of the ligamenta subflava. 2, The 
capsular ligament of one side. 




140 



LIGAMENTS OF THE VERTEBRAL COLUMN. 



animals, by a thin slip from the spinous process of each of the cervical 
vertebrae. 

Transverse Processes. — The inter-transverse ligaments are thin and 
membranous ; they are found only between the transverse processes of the 
lower dorsal vertebrae. 

2. Articulation of the Atlas with the Occipital bone. — The ligaments 
of this articulation are seven in number, — 

Two anterior occipito-atloid, Posterior occipito-atloid, 

Lateral occipito-atloid, Two capsular. 

Of the two anterior ligaments, one is a rounded cord, situated in the 
middle line, and superficially to the other. It is attached above, to the 
basilar process of the occipital bone ; and below, to the anterior tubercle 
of the atlas. The deeper ligament is a broad membranous layer, attached 
above, to the margin of the occipital foramen ; and below, to the whole 
length of the anterior arch of the atlas. It is in relation in front with the 
recti antici minores, and behind with the odontoid ligaments. 



Fig. 75.* 





The posterior ligament is thin and membranous ; it is attached above, 
to the margin of the occipital foramen ; and below, to the posterior arch 
of the atlas. It is closely adherent to the dura mater, by its inner surface ; 
and forms a ligamentous arch at each side, for the passage of the vertebral 
arteries and first cervical nerves. It is in relation posteriorly with the recti 
postici minores and obliqui superiores. 

The lateral ligaments are strong fasciculi of ligamentous fibres, attached 
below, to the base of the transverse process of the atlas at each side, and 
above, to the transverse process of the occipital bone. With a ligamentous 
expansion derived from the vaginal process of the temporal bone, these 

* An anterior view of the ligaments connecting the atlas, the axis, and the orcipital 
bone. A transverse section has been carried through the base of the skull, dividing the 
basilar process of the occipital bone and the petrous portions of the temporal bones. 
1. The anterior round occipito-atloid ligament. 2. The anterior broad occipito-atloid 
ligament. 3. The commencement of the anterior common ligament. 4. The anterior 
atlo-axoid ligament, which is continuous inferiorly with the commencement of the ante- 
rior common ligament. 5. One of the atlo-axoid capsular ligaments; the one on the 
opposite side has been removed, to show the approximated surfaces of the articular 
processes (6). 7. One of the occipito-atloid capsular ligaments. The most external of 
these fibres constitute the lateral occipito-atloid ligament. 

f The posterior ligaments of the occipito-atloid, and atlo-axoid articulations. 1. The 
atlas. 2. The axis. 3. The posterior ligament of the occipito-atloid articulation. 4, 4. 
The capsular and lateral ligaments of this articulation. 5. The posterior ligament of the 
atlo-axoid articulation. 6, 6. Its capsular ligaments. 7. The first of the ligamentum 
subflava passing between the axis and the third cervical vertebra. 8, 8. The capsular 
ligaments of those vertebrae. 



LIGAMENTS OF THE VERTEBRAL COLUMN. 141 

ligaments form a strong sheath around the vessels and nerves which pass 
through the carotid and jugular foramina. 

The capsular ligaments are the thin and loose ligamentous capsules 
which surround the synovial membranes of the articulations between the 
condyles of the occipital bone and the superior articular processes of the 
atlas. The ligamentous fibres are most numerous upon the anterior and 
external part of the articulation. 

The movements taking place between the cranium and atlas, are those 
of flexion and erection, giving rise to the forward nodding of the head. 
When this motion is increased to any extent the whole of the cervical 
region concurs in its production. 

3. Articulation of the Axis with the Occipital bone.— The ligaments of 
this articulation are three in number, — 

Occipito-axoid, , Two odontoid. 

The occipito-axoid ligament (apparatus ^ 

ligamentosus colli) is a broad band, lg ' 

which covers in the odontoid process and 
its ligaments. It is attached below to 
the body of the axis, where it is continu- 
ous with the posterior common ligament ; 
superiorly it is inserted by a broad ex- 
pansion, into the basilar groove of the 
occipital bone. It is firmly connected 
opposite the body of the axis, with the 
dura mater ; and sometimes is described 
as consisting of a central and two lateral 
portions ; this, however, is an unnecessary refinement. 

The odontoid ligaments (alar) are two short and thick fasciculi of fibres, 
which pass outwards from the apex of the odontoid process, to the sides 
of the occipital foramen and condyles. A third and smaller fasciculus 
(ligamentum suspensorium), or middle straight ligament, proceeds from 
the apex of the odontoid process to the anterior margin of the foramen 
magnum. 

These ligaments serve to limit the extent to which rotation of the head 
may be carried, hence they are termed check ligaments. 

4. Articulation of the Atlas with the Axis. — The ligaments of this arti- 
culation arefve in number, — 

Anterior atlo-axoid, Two capsular, 

Posterior atlo-axoid, Transverse. 

The anterior ligament consists of ligamentous fibres, which pass from 
the anterior tubercle and arch of the atlas to the base of the odontoid pro- 
cess and body of the axis, where they are continuous with the commence- 
ment of the anterior common ligament. 

* The upper part of the vertebral canal, opened from behind in order to, show the 
occipito-axoid ligament. 1. The basilar portion of the sphenoid bone. 2. Section of the 
occipital bone. 3. The atlas, its posterior arch removed. 4. The axis, the posterior 
arch also removed. 5. The occipito-axoid ligament, rendered prominent at its middle 
by the projection of the odontoid process. 6. Lateral and capsular ligament of the oc- 
cipito-atloid articulation. 7. Capsular ligament between the articulating processes of 
the atlas and axis. 





142 LIGAMENTS OF THE LOWER JAW. 

The posterior ligament is a thin and membranous layer, passing be- 
tween the posterior arch of the atlas and the laminae of the axis. 

The capsular ligaments surround the articular processes of the atlas and 
axis ; they are loose, to permit of the freedom of movement which sub- 
sists between these vertebrae. The ligamentous fibres are most numerous 
on the outer and anterior part of the articulation, and the synovial mem- 
brane usually communicates with the synovial cavity between the trans- 
verse ligament and the odontoid process. 

The transverse ligament is a strong ligamentous band, which arches 
across the area of the ring of the atlas from a rough tubercle upon the 

inner surface of one articular process to a 
Fi s- 78 -* similar tubercle on the other. It serves 

to retain the odontoid process of the axis, 
in connexion with the anterior arch of the 
atlas. As it crosses the odontoid process, 
some fibres are sent downwards to be at- 
tached to the body of the axis, and others 
pass upwards to be inserted into the basi- 
lar process of the occipital bone ; hence 
the ligament has a cross-like appearance, 
derived from these appendices, and has 
been denominated cruciform. A synovial 
membrane is situated between the transverse ligament and the odontoid 
process ; and another between that process and the inner surface of the 
anterior arch of the atlas. 

Actions. — It is the peculiar disposition of this ligament in relation to 
the odontoid process, that enables the atlas, and with it the entire cra- 
nium, to rotate upon the axis ; the perfect freedom of movement between 
these bones being insured by the two synovial membranes. The lower 
part of the ring, formed by the transverse ligament with the atlas, is 
smaller than the upper, while the summit of the odontoid process is larger 
than its base ; so that the process is still retained in its position by the 
transverse ligament, when the other ligaments are cut through. The ex- 
tent to which the rotation of the head upon the axis can be carried is de- 
termined by the odontoid ligaments. The odontoid process with its liga- 
ments is covered in by the occipito-axoid ligament. 

5. Articulation of the lower jaw. — The lower jaw has properly but one 
ligament, the external lateral ; the ligaments usually described are three 
in number ; to which may be added, as appertaining to the mechanism 
of the joint, an interarticular fibrous cartilage, and two synovial mem- 
branes, — 

External lateral, Interarticular fibrous-cartilage, 

Internal lateral, Two synovial membranes, 

Capsular. 

* A posterior view of the ligaments connecting the atlas, the axis, and the occipital 
bone. The posterior part of the occipital bone has been sawn away, and the arches 
of the atlas and axis removed. 1. The superior part of the occipito-axoid ligament, 
which has been cut away in order to show the ligaments beneath. 2. The transverse 
ligament of the atlas. 3, 4. The ascending and descending slips of the transverse liga- 
ment, which have obtained for it the title of cruciform ligament. 5. One of the odon- 
toid ligaments ; the fellow ligament is seen on the opposite side. 6. One of the occi- 
pito-atloid capsular ligaments. 7. One of the atlo-axoid capsular ligaments. 



LIGAMENTS OF THE LOWER JAW. 



143 



The external lateral ligament is a short and thick band of fibres, pass- 
ing obliquely backwards from the tubercle of the zygoma, to the external 
surface of the neck of the lower jaw. It is in relation, externally with the 
integument of the face, and internally with the two synovial membranes 
of the articulation and the interarticular cartilage. The external lateral 
ligament acts conjointly with its fellow of the opposite side of the head in 
the movements of the jaw. 

The internal lateral ligament has no connexion with the articulation of 
the lower jaw, and is incorrectly named in relation to the joint ; it is a thin 
aponeurotic expansion extending from the extremity of the spinous pro- 
cess of the sphenoid bone to the margin of the dental foramen. It is 
pierced at its insertion, by the mylo-hyoidean nerve. 



Fig. 79* 



Fig. 80.f 





A triangular space is left between the internal lateral ligament and the 
neck of the jaw, in which are situated the internal maxillary artery and 
auricular nerve, the inferior dental artery and nerve, and a part of the ex- 
ternal pterygoid muscle ; internally it is in relation with the internal ptery- 
goid muscle. 

The capsular ligament consists of a few irregular ligamentous fibres, 
which pass from the edge of the glenoid cavity to the neck of the lower 
jaw, upon the inner and posterior side of the articulation. These fibres 
scarcely deserve consideration as a distinct ligament. 

The interarticular fibrous cartilage is a thin oval plate, thicker at the 
edges than in the centre, and placed horizontally between the head of the 
condyle of the lower jaw and the glenoid cavity. It is connected by its 
outer border with the external lateral ligament, and in front receives some 
fibres of the external pterygoid muscle. Occasionally it is incomplete in 
the centre. It divides the joint into two distinct cavities, the one being 
above and the other below the cartilage. 

The synovial membranes are situated the one above, the other below, 
the fibrous cartilage, the former being the larger of the two. When the 
fibrous cartilage is perforate, the synovial membranes communicate. 

* An external view of the articulation of the lower jaw. 1. The zygomatic arch. 
2. The tubercle of the zygoma. 3. The ramus of the lower jaw. 4. The mastoid por- 
tion of the temporal bone. 5. The external lateral ligament. 6. The stylo-maxillary 
ligament. 

f An internal view of the articulation of the lower jaw. 1. A section through the pe- 
trous portion of the temporal bone and spinous process of the sphenoid. 2. An internal 
view of the ramus, and part of the body of the lower jaw. 3. The internal portion of 
the capsular ligament. 4. The internal lateral ligament. 5. A small interval at its in- 
sertion, through which the mylo-hyoidean nerve passes. 6. The stylo-maxillary liga- 
ment, a process of the deep cervical fascia. 



144 



LIGAMENTS OF THE RIBS. 



Fig. 81 * 




Besides the lower jaw, there are several other joints provided with a 

complete interarticular cartilage, and, con- 
sequently, with two synovial membranes ; 
they are, the sterno-clavicular articulation, 
the acromio-clavicular and the articulation 
of the ulna with the cuneiform bone. 

The interarticular fibrous cartilages of 
the knee-joint are partial, and there is but 
one synovial membrane. 

The articulations of the heads of the 

ribs with the vertebrae have two synovial 

membranes, separated by an interarticular 

ligament, without fibrous cartilage. 

Actions. — The movements of the lower jaw are depression, by which 

the mouth is opened ; elevation, by which it is closed ; a forward and 

backward movement, and a movement from side to side. 

In the movement of depression, the interarticular cartilage glides for- 
wards on the eminentia articularis, carrying with it the condyle. If this 
movement be carried too far, the superior synovial membrane is ruptured. 
and dislocation of the fibro-cartilage with its condyle into the zygomatic 
fossa occurs. In elevation, the fibrous cartilage and condyle are returned 
to their original position. The forward and backward movement is a 
gliding of the fibro-cartilage upon the glenoid articular surface, in the 
antero-posterior direction ; and the movement from side to side, in the 
lateral direction. 

6. Articulation of the Ribs with the Vertebrce. — The ligaments of these 
articulations are so strong as to render dislocation impossible, the neck of 
the rib would break before displacement could occur ; they are divisible 
into two groups : — 1. Those connecting the head of the rib with the bodies 
of the vertebra ; and, 2. Those connecting the neck and tubercle of the, rib 
with the transverse processes. They are — 



Interarticular ligament, 
Two synovial membranes. 



1st Group. 

Anterior costo- vertebral or stellate, 
Capsular, 

2d Group. 

Anterior costo-transverse, 
♦ Middle costo-transverse, 

Posterior costo-transverse. 

The anterior costo-vertebral or stellate ligament (fig. 72) consists of 
three short bands of ligamentous fibres that radiate from the anterior part 
of the head of the rib. The superior band passes upwards, and is attached 
to the vertebra above : the middle fasciculus is attached to the interverte- 
bral substance ; and the inferior, to the vertebrae below. 

* In this sketch a section has been carried through the joint, in order to show the 
natural position of the interarticular fibro-cartilage, and the manner in which it is 
adapted to the difference of form of the articulating surfaces. 1. The glenoid fossa. 
2. The eminentia articularis. 3. The interarticular fibro-cartilaye. 4. The superior 
synovial cavity. 5. The inferior synovial cavity. G. An interarticular fibro-cartilage, 
removed from the joint, in order to show its oval and concave form ; it is seen from 
below. 



LIGAMENTS OF THE RIBS. 145 

In the first, eleventh, and twelfth ribs, the three fasciculi are attached 
to the body of the corresponding vertebra. 

The capsular ligament is a thin layer of ligamentous fibres, surrounding 
the joint in the interval left by the anterior ligament ; it is thickest above 
and below the articulation, and protects the synovial membranes. 

The interarticular ligament is a thin band which passes between the 
sharp crest on the head of the rib and the intervertebral substance. It 
divides the joint into two cavities, which are each furnished with a sepa- 
rate synovial membrane. The first, eleventh, and twelfth ribs have no 
interarticular ligament, and consequently but one synovial membrane. 

The anterior costo-transverse ligament is a broad band composed of 
several fasciculi, which ascends from the crest-like ridge on the neck 
of the rib, to the transverse process immediately above. This liga- 
ment separates the anterior from the posterior branch of the intercostal 
nerves. 

The middle costo-transverse ligament is a very strong interosseous liga- 
ment, passing directly between the posterior surface of the neck of the rib, 
and the transverse process against which it rests. 

The posterior costo-transverse ligament is a small but strong fasciculus, 
passing obliquely from the tubercle of the rib, to the apex of the trans- 
verse process. The articulation between the tubercle of the rib and the 
transverse process is provided with a small synovial membrane. 

There is no anterior costo-transverse ligament to the first rib ; and only 
rudimentary posterior costo-transverse ligaments to the eleventh and 
twelfth ribs. 

Actions. — The movements permitted by the articulations of the ribs, 
are upwards and downwards, and slightly for- 
wards and backwards ; the movement increas- Fi g . 82* 
ing in extent from the head to the extremity of 
the rib. The forward and backward move- 
ment is very trifling in the seven superior, but 
greater in the inferior ribs ; the eleventh and 
twelfth are very movable. 

7. Articulation of the Ribs with the Sternum, 
and with each other. — The ligaments of the 
costo-stemal articulations are, — 

Anterior costo-stemal, 
Posterior costo-sternal, 
Superior costo-sternal, 
Inferior costo-sternal, 
Synovial membranes. 

The anterior costo-sternal ligament is a thin band of ligamentous fibres, 
that passes in a radiated direction from the extremity of the costal carti- 
lage to the anterior surface of the sternum, and intermingles its fibres with 
those of the ligament of the opposite side and with the tendinous fibres of 
origin of the pectoralis major muscle. 

* A posterior view of a part of the thoracic portion of the vertebral column, showing 
the ligaments connecting the vertebrae with each other, and the ribs with the vertebrae. 
I, 1. The supra-spinous ligament. 2, 2. The ligamenta subflava, connecting the 
laminae 3. The anterior costo-transverse ligament. 4. The posterior costo-transverse 
ligaments. 

13 K 




146 LIGAMENTS OF THE PELVIS. 

The posterior costo-sternal ligament is much smaller than the anterior, 
and consists only of a thin fasciculus of fibres situated on the posterior 
surface of the articulation. 

The superior and inferior costo-sternal ligaments are narrow fasciculi 
corresponding with the breadth of the cartilage, and connecting its supe- 
rior and inferior border with the side of the sternum. 

The synovial membrane is absent in the articulation of the first rib, its 
cartilage being usually continuous with the sternum ; that of the second 
rib has an interarticular ligament, with two synovial membranes. 

The sixth and seventh ribs have several fasciculi of strong ligamentous 
fibres, passing from the extremity of their cartilages to the anterior surface 
of the ensiform cartilage, which latter they are intended to support. 
They are named the costo-xiphoid ligaments. 

The six, seventh, and eighth, and sometimes the fifth and the ninth 
costal cartilages, have articulations with each other, and a perfect synovial 
membrane. They are connected by ligamentous fibres which pass from 
one cartilage to the other, external and internal ligaments. 

The ninth and tenth are connected at their extremities by ligamentous 
fibres, but have no synovial membranes. 

Actions. — The movements of the costo-sternal articulations are very 
trifling ; they are limited to a slight sliding motion. The first rib is the 
least, and the second the most movable. 

8. Articulation of the Sternum. — The pieces of the sternum are con- 
nected by means of a thin plate of interosseous cartilage placed between 
each, and by an anterior and posterior ligament. The fibres of the ante- 
rior sternal ligament are longitudinal in direction, but so blended with the 
anterior costo-sternal ligaments, and the tendinous fibres of origin of the 
pectoral muscles, as scarcely to be distinguished as a distinct ligament. 
The posterior sternal ligament is a broad smooth plane of longitudinal 
fibres, placed upon the posterior surface of the bone, and extending from 
the manubrium to the ensiform cartilage. These ligaments contribute 
very materially to the strength of the sternum and to the elasticity of the 
front of the chest. 

9. Articulation of the Vertebral Column urith the Pelvis. — The last 
lumbar vertebra is connected with the sacrum by the same ligaments with 
which the various vertebrae are connected to each other ; viz. the anterior 
and posterior common ligaments, intervertebral substance, ligamenta sub- 
flava, capsular ligaments, and inter and supra-spinous ligaments. 

There are, however, two proper ligaments connecting the vertebral 
column with the pelvis ; these are, the 

Lumbo-sacral, Lumbo-iliac. 

The lumbosacral ligament is a thick triangular fasciculus of ligamentous 
fibres, connected above with the transverse process of the last lumbar ver- 
tebra; and below with the posterior part of the upper border of the 
sacrum. 

The lumbo-iliac ligament passes from the apex of the transverse process 
of the last lumbar vertebra to that part of the crest of the ilium which sur- 
mounts the sacro-iliac articulation. It is triangular in form. 

10. The Articulations of the Pelvis. — The ligaments belonging to the 
articulations of the pelvis are divisible into four groups . 1 . Those connect- 



LIGAMENTS OF THE PELVIS. 147 

ing the sacrum and ilium ; 2. those passing between the sacrum and is- 
chium ; 3. between the sacrum and coccyx ; and 4. between the two pubic 
bones. 

1st, Between the sacrum and ilium. 
Sacro-iliac anterior, 
Sacro-iliac posterior. 

2d, Between the sacrum and ischium. 
Sacro-ischiatic anterior (short), 
Sacro-ischiatic posterior (long). 

3d, Between the sacrum and coccyx. 
Sacro-coccy|;ean anterior, 
Sacro-coccygean posterior. 

4th, Between the ossa pubis. 
Anterior pubic, 
Posterior pubic, 
Superior pubic, 
Sub-pubic, 
Interosseous fibro-cartilage. 

1. Between the Sacrum and Ilium. — The anterior sacro-iliac ligament 
consists of numerous short ligamentous fibres, which pass from bone to 
bone on the anterior surface of the joint. 

The posterior sacro-iliac or interosseous ligament is composed of nu- 
merous strong fasciculi of ligamentous fibres, which pass horizontally be- 
tween the rough surfaces in the posterior half of the sacro-iliac articulation, 
and constitute the principal bond of connexion between the sacrum and 
the ilium. One fasciculus of this ligament, longer and larger than the 
rest, is distinguished, from its direction, by the name of the oblique sacro- 
iliac ligament. It is attached, by one extremity, to the posterior superior 
spine of the ilium ; and, by the other, to the third transverse tubercle on 
the posterior surface of the sacrum. 

The surfaces of the two bones forming the sacro-iliac articulation are 
partly covered with cartilage, and partly rough and connected by the in- 
terosseous ligament. The anterior or auricular half is coated with carti- 
lage, which is thicker on the sacrum than on the ilium. The surface of 
the cartilage is irregular, and provided with a very delicate synovial mem- 
brane, which cannot be demonstrated in the adult ; but is apparent in the 
young subject, and in the female during pregnancy. 

2. Between the Sacrum and Ischium. — The anterior or lesser sacro-ischi- 
atic ligament is thin, and triangular in form ; it is attached by its apex to 
the spine of the ischium, and by its broad extremity to the side of the sa- 
crum and coccyx, interlacing its fibres with the greater sacro-ischiatic 
ligament. 

The anterior sacro-ischiatic ligament is in relation in front with the coc- 
cygeus muscle, and behind with the posterior ligament, with which its 
fibres are intermingled. By its upper border it forms a part of the lower 
boundary of the great sacro-ischiatic foramen, and by the lower, a part of 
the lesser sacro-ischiatic foramen. 



148 



LIGAMENTS OF THE PELVIS. 



The posterior or greater sacro-ischiatic ligament, considerably larger, 
thicker, and more posterior than the preceding, is narrower in the middle 
than at each extremity. It is attached, by its smaller end, to the inner 
margin of the tuberosity and ramus of the ischium, where it forms a falci- 
form process, which protects the internal pudic artery, and is continuous 
with the obturator fascia. By its larger extremity it is inserted into the side 
of the coccyx, sacrum, and posterior inferior spine of the ilium. 



Fig. 83* 



Fig. 84.f 





The posterior sacro-ischiatic ligament is in relation in front with the an- 
terior ligament, and behind with the gluteus maximus, to some of the 
fibres of which it gives origin. By its superior border it forms part of the 
lesser ischiatic foramen, and by its lower border, a part of the boundary 
of the perineum. It is pierced by the coccygeal branch of the ischiatic 
artery. The two ligaments convert the sacro-ischiatic notches into 
foramina. 

3. Between the Sacrum and Coccyx. — The anterior sacro-coccygean liga- 
ment is a thin fasciculus passing from the anterior surface of the sacrum to 
the front of the coccyx. 

The posterior sacro-coccygean ligament is a thick ligamentous layer, 
w r hich completes the lower part of the sacral canal, and connects the 

* The ligaments of the pelvis and hip joint. 1. The lower part of the anterior com- 
mon ligament of the vertebra?, extending downwards over the front of the sacrum. 2. 
The lumbo-sacral ligament. 3. The lumbo-iliac iigament. 4. The anterior sacro-iliac 
ligaments. 5. The obturator membrane. 6. Poupart's ligament. 7. Gimbernat s liga- 
ment. 8. The capsular ligament of the hip-joint. 9. The ilio-femoral or accessory 
ligament. 

\ Ligaments of the pelvis and hip joint. The view is taken from the side. 1. The 
oblique sacro-iliac ligament. The other fasciculi of the posterior sacro-iliac ligaments 
are not seen in this view of the pelvis. 2. The posterior sacro-ischiatic ligament. 3. 
The anterior sacro-ischiatic ligament. 4. The great sacro-ischiatic foramen. 5. The 
lesser sacro-ischiatic foramen. 6. The cotyloid ligament of the acetabulum. 7. The 
ligamentum teres. 8. The cut edge of the capsular ligament, showing its extent poste- 
riorly as compared with its anterior attachment. 9. The obturator membrane only partly 
seen. 



LIGAMENTS OF THE UPPER EXTREMITY. 149 

sacrum with the coccyx posteriorly, extending as far as the apex of the 
latter bone. 

Between the two bones is a thin disc of soft fibrous cartilage. In 
females there is frequently a small synovial membrane. This articulation 
admits of a certain degree of movement backwards during parturition. 

The ligaments connecting the different pieces of the coccyx consist of a 
few scattered anterior and posterior fibres, and a thin disc of interosseous 
cartilage : they exist only in the young subject ; in the adult the pieces 
become ossified. 

4. Between the Ossa Pubis. — The anterior pubic ligament is composed 
of ligamentous fibres, which pass obliquely across the union of the two 
bones from side to side, and form an interlacement in front of the sym- 
physis. 

The posterior pubic ligament consists of a few irregular fibres uniting 
the pubic bones posteriorly. 

The superior pubic ligament is a thick band of fibres connecting the 
angles of the pubic bones superiorly, and filling the inequalities upon the 
surface of the bones. 

The sub-pubic ligament is a thick arch of fibres connecting the two bones 
inferiorly, and forming the upper boundary of the pubic arch. 

The interosseous Jibro-cartilage uni^s the two surfaces of the pubic 
bones, in the same manner as the intervertebral substance connects the 
bodies of the vertebrae. It resembles the intervertebral substance also in 
being composed of oblique fibres disposed in concentric layers, which are 
more dense towards the surface than near the centre. It is thick in front, 
and thin behind. A synovial membrane is sometimes found in the poste- 
rior half of the articulation. 

This articulation becomes movable towards the latter term of pregnancy, 
and admits of a slight degree of separation of its surfaces. 

The obturator ligament or membrane is not a ligament of articulation, 
but simply a tendino-fibrous membrane stretched across the obturator 
foramen. It gives attachment by its surfaces, to the two obturator mus- 
cles, and leaves a space in the upper part of the foramen, for the passage 
of the obturator vessels and nerve. 

The numerous vacuities in the walls of the pelvis, and their closure by 
ligamentous structures, as in the case of the sacro-ischiatic fissures and 
obturator foramina, serve to diminish very materially the pressure on the 
soft parts during the passage of the head of the foetus through the pelvis 
in parturition. 

LIGAMENTS OF THE UPPER EXTREMITY. 

The Ligaments qftlie upper extremity may be arranged in the order of 
the articulations between the different bones ; they are, the 

1. Sternoclavicular articulation. 8. Articulation between the carpal 

2. Scapuloclavicular articulation. bones. 

3. Ligaments of the scapula. 9. Carpo-metacarpal articulation. 

4. Shoulder joint. 10. Metacarpo-phalangeal articula- 

5. Elbow joint. tion. 

6. Radio-ulnar articulation. 11. Articulation of the phalanges. 

7. Wrist joint. 

1. Sterno-clavicular Articulation. — The sternoclavicular is an arthro- 
dial articulation ; its ligaments are, 
13* 



150 



LIGAMEINTS OF THE UPPER EXTREMITY. 



Anterior sterno-clavicular, 
Posterior sterno-clavicular, 
Inter-clavicular, 
Costo-clavicular (rhomboid), 

Interarticular fibro-cartilage, 

Two synovial membranes. 

The anterior sterno-clavicular ligament is a broad ligamentous layer, 
extending obliquely downwards and forwards, and covering the anterior 
aspect of the articulation. This ligament is in relation by its anterior sur- 
face with the integument and with the sternal origin of the sterno-mastoid 
muscle ; and behind with the interarticular fibro-cartilage and synovial 
membranes. 

The posterior sterno-clavicular ligament is a broad fasciculus, covering 
the posterior surface of the articulation. It is in relation by its anterior 
surface with the interarticular fibro-cartilage and synovia] membranes, and 
behind with the sterno-hyoid muscle. 

The two ligaments are continuous at the upper and lower part of the 
articulation, so as to form a complete capsule around the joint. 

The interclavicular ligament is a cord-like band which crosses from the 
extremity of one clavicle to the other, and is closely connected with the 
upper border of the sternum. It is separated by areolar tissue from the 
sterno-thyroid muscles. 

The costo-clavicular ligament (rhomboid) is a thick fasciculus of fibres, 
connecting the sternal extremity of the clavicle with the cartilage of the 
first rib. It is situated obliquely between the rib and the under surface 
of the clavicle. It is in relation in front with the tendon of origin of the 
subclavius muscle, and behind with the subclavian vein. 

Actions. — The movements of the sterno-clavicular articulation, are a 
gliding movement of the fibro-cartilage with the clavicle upon the articular 
surface of the sternum in the directions forwards, backwards, upwards, 
and downwards ; and circumduction. This articulation is the centre of 
the movements of the shoulder. 

It is the rupture of the rhomboid ligament in dislocation of the sternal 
end of the clavicle that gives rise to the deformity peculiar to this acci- 
dent. The interarticular fibro-cartilage is 

nearly circular in form, and thicker at 
the edges than in the centre. It is at- 
tached above to the clavicle ; below to 
the cartilage of the first rib ; and through- 
out the rest of its circumference to the 
anterior and posterior sterno-clavicular 
ligaments ; it divides the joint into two 
cavities, which are lined by distinct sy- 
novial membranes. This cartilage is 
sometimes pierced through its centre, 
and not unfrequently deficient, to a greater 
or less extent, in its lower part. 

• The ligaments of the sterno-clavicular and costo-sternal articulations. 1. The ante- 
rior sterno-clavicular ligament. 2. The inter-clavicular ligament. 3. The costo-clavi- 
cular or rhomboid ligament, seen on both sides. 4. The interarticular fibro-cartilage, 
brought into view by the removal of the anterior and posterior ligaments. 5. The an- 
terior costo-sternal ligaments of the first and second ribs. 



Fig. 85* 




LIGAMENTS OF THE SCAPULA. 



151 



2. Scapulo-claviatlar Articulation. — The ligaments of the scapular end 
of the clavicle are, the 

Superior acromio-clavicular, 
Inferior acromio-clavicular, 
Coraco-clavicular (trapezoid and conoid), 

Interarticular fibro-cartilage, 

Two synovial membranes. 

The superior acromio-clavicular ligament is a moderately thick plane 
of superimposed fibres passing between the extremity of the clavicle and 
the acromion, upon the upper surface of the joint. 

The inferior acromio-clavicular ligament is a thin plane situated upon 
the under surface. These two ligaments are continuous with each other 
in front and behind, and form a complete capsule around the joint. 

The coraco-clavicular ligament (trapezoid, conoid) is a thick fasciculus 
of ligamentous fibres, passing obliquely between the base of the coracoid 
process and the under surface of the clavicle, and holding the end of the 
clavicle in firm connexion with the scapula. When seen from before, it 
has a quadrilateral form : hence it is named trapezoid ; and examined from 
behind, it has a triangular form, the base being upwards ; hence another 
name, conoid. 

The interarticular fibro-cartilage is often indistinct, from having partial 
connexions with the fibro-cartilaginous surfaces of the two bones between 
which it is placed, and not unfrequently absent. When partial, it occu- 
pies the upper part of the articulation. The synovial membranes are very 
delicate. There is, of course, but one, when the fibro-cartilage is incom- 
plete. 

Actions. — The acromio-clavicular articulation admits of two movements, 
the gliding of the surfaces upon each other ; and the rotation of the sca- 
pula upon the extremity of the clavicle. 

3. The Proper ligaments of the Scapula 

are the Fi s- 86 * 

Coraco-acromial, 
Transverse. 

The coraco-acromial ligament is a broad 
and thick triangular band, which forms a pro- 
tecting arch over the shoulder joint. It is 
attached by its apex to the point of the acro- 
mion process, and by its base to the external 
border of the coracoid process its whole 
length. This ligament is in relation above 
with the under surface of the deltoid muscle ; 
and below with the tendon of the supra-spi- 
natus muscle, a bursa mucosa being usually 
interposed. 

The transverse or coracoid ligament is a 
narrow but strong fasciculus which crosses 

* The ligaments of the scapula and shoulder joint. 1. The superior acromio-clavicu- 
lar ligament. 2. The coraco-clavicular ligament ; this aspect of the ligament is named 
trapezoid. 3. The coraco-acromial ligament. 4. The transverse ligament. 5. The 
capsular ligament. 6. The coraco-humeral ligament. 7. The long tendon of the biceps 
issuing from the capsular ligament, and entering the bicipital groove. 




152 SHOULDER JOINT — ELBOW JOINT. 

the notch in the upper border of the scapula, from the base of the cora- 
coid process, and converts it into a foramen. The supra-scapular nerve 
passes through this foramen. 

4. Shoulder Joint. — The scapulo-humeral articulation is an enarthrosis, 
or ball-and-socket joint — its ligaments are, the 

Capsular, 

Coraco-humeral, 

Glenoid. 

The capsular ligament completely encircles the articulating head of the 
scapula and the head of the humerus, and is attached to the neck of each 
bone. It is thick above, where resistance is most required, and is 
strengthened by the tendons of the supra-spinatus, infra-spinatus, teres 
minor, and subscapularis muscles : below it is thin and loose. The cap- 
sule is incomplete at the point of contact with the tendons, so that they 
obtain upon their inner surface a covering of synovial membrane. 

The coraco-humeral ligament is a broad band which descends obliquely 
outwards from the border of the coracoid process to the greater tuberosity 
of the humerus, and serves to strengthen the superior and anterior part of 
the capsular ligament. 

The glenoid ligament is the prismoid band of fibro-cartilage, which is 
attached around the margin of the glenoid cavity for the purposes of pro- 
tecting its edges, and deepening its cavity. It divides superiorly into two 
slips which are continuous with the long tendon of the biceps ; hence the 
ligament is frequently described as being formed by the splitting of that 
tendon. The cavity of the articulation is traversed by the long tendon 
of the biceps, which is enclosed in a sheath of synovial membrane in its 
passage through the joint. 

The synovial membrane of the shoulder joint is very extensive ; it com- 
municates anteriorly through an opening in the capsular ligament with a 
large bursal sac, which lines the under surface of the tendon of the sub- 
scapularis muscle. Superiorly, it frequently communicates through another 
opening in the capsular ligament with a bursal sac belonging to the infra- 
spinatus muscle ; and it moreover forms a sheath around that portion of 
the tendon of the biceps, which is included within the joint. 

The muscles immediately surrounding the shoulder* joint are the sub- 
scapularis, supra-spinatus, infra-spinatus, teres minor, long head of the 
triceps and deltoid ; the long tendon of the biceps is within the capsular 
ligament. 

Actions. — The shoulder joint is capable of every variety of motion, viz. 
of movement forwards and backwards, of abduction and adduction, of 
circumduction and rotation. 

5. Elbow Joint. — The elbow is a ginglymoid articulation ; its ligaments 
are four in number, — 

Anterior, Internal lateral, 

Posterior, External lateral. 

The anterior ligament is a broad and thin membranous layer, descend- 
ing from the anterior surface of the humerus, immediately above the joint, 
to the coronoid process of the ulna and orbicular ligament. On each side 
it is connected with the lateral ligaments. It is composed of fibres which 
pass in three different directions, vertical, transverse, and oblique, the lat- 



RADIOULNAR ARTICULATION. 



153 



Fig. 87.* 



Fig. 88.f 




ter being extended from within outwards to the orbicular ligament, into 
which they are attached interiorly. This ligament is covered in by the 
brachialis anticus muscle. 

The posterior ligament is a broad and 
loose layer passing between the posterior 
surface of the humerus and the anterior 
surface of the base of the olecranon, and 
connected at each side with the lateral 
ligaments. It is covered in by the ten- 
don of the triceps. 

The internal lateral ligament is a thick 
triangular layer, attached above, by its 
apex, to the internal condyle of the hu- 
merus ; and below, by its expanded bor- 
der, to the margin of the greater sigmoid 
cavity of the ulna, extending from the 
coronoid process to the olecranon. At 
its insertion it is intermingled with some 
transverse fibres. The internal lateral 
ligament is in relation posteriorly with 
the ulnar nerve. 

The external lateral ligament is a strong 
and narrow band, which descends from 
the external condyle of the humerus, to 
be inserted into the orbicular ligament, 

and into the ridge on the ulna, with which the posterior part of the latter 
ligament is connected. This ligament is closely united with the tendon 
of origin of the supinator brevis muscle. 

The synovial membrane is extensive, and is reflected from the cartila- 
ginous surfaces of the bones upon the inner surface of the ligaments. It 
surrounds inferiorly the head of the radius, and forms an articulating sac 
between it and the lesser sigmoid notch. 

The muscles immediately surrounding, and in contact with, the elbow 
joint, are in front, the brachialis anticus; to the inner side, the pronator 
radii teres, flexor sublimis digitorum, and flexor carpi ulnaris ; externally, 
the extensor carpi radialis brevior, extensor communis digitorum, entensor 
carpi ulnaris, anconeus, and supinator brevis ; and behind, the triceps. 

Actions. — The movements of the elbow joint are flexion and extension, 
which are performed with remarkable precision. The extent to which 
these movements are capable of being effected, is limited in front by the 
coronoid process, and behind by the olecranon. 

6. The Radio-ulnar Articulation. — The radius and ulnar are firmly held 
together by ligaments which are connected with both extremities of the 
bones, and with the shaft ; they are, the 

Orbicular, Anterior inferior, 

Oblique, Posterior inferior, 

Interosseous, Interarticular fibro-cartilage. 

* An internal view of the ligaments of the elbow joint. 1. The anterior ligament. 
2. The internal lateral ligament. 3. The orbicular ligament. 4. The oblique ligament. 
5. The interosseous ligament. 6. The internal condyle of the humerus, which conceab 
the posterior ligament. 

■|" An external view of the elbow joint. 1. The humerus. 2. The ulna. 3. The ra 



154 



RADIOULNAR ARTICULATION. 



Fig. 89 * 




The orbicular ligament (annular, coronary) is a firm 
band several lines in breadth, which surrounds the 
head of the radius, and is attached by each end to the 
extremities of the lesser sigmoid cavity. It is strong- 
est behind where it receives the external lateral liga- 
ment, and is lined on its inner surface by a reflection 
of the synovial membrane of the elbow joint. 

The rupture of this ligament permits of the disloca- 
tion of the head of the radius. 

The oblique ligament (called also ligamentum teres 
in contradistinction from the interosseous ligament) is 
a narrow slip of ligamentous fibres, descending 
obliquely from the base of the coronoid process of the 
ulna to the inner side of the radius, a little below its 
tuberosity. 

The interosseus ligament is a broad and thin plane 
of aponeurotic fibres passing obliquely dow T nwards from the sharp ridge 
on the radius to that on the ulna. It is deficient superiorly, is broader 
in the middle than at each extremity, and is perforated at its lower part 
for the passage of the anterior interosseous artery. The posterior interos- 
seous artery passes backwards between the oblique ligament and the upper 
border of the interosseous ligament. This ligament affords an extensive 
surface for the attachment of muscles. 

The interosseous ligament is in relation, in front, with the flexor pro- 
fundus digitorum, the flexor longus pollicis, and pronator quadratus mus- 
cle, and with the anterior interosseous artery and nerve ; and behind with 
the supinator brevis, extensor ossis metacarpi pollicis, extensor primi 
internodii pollicis, extensor secundi internodii pollicis, and extensor indicis 
muscle, and near the wrist with the anterior interosseous artery and pos- 
terior interosseous nerve. 

The anterior inferior ligament is a thin fasciculus of fibres, passing 
transversely between the radius and ulna. 

The posterior inferior ligament is also thin and loose, and has the same 
disposition on the posterior surface of the articulation. 

The interarticular, or triangular fbro-cartilage, acts the part of a liga- 
ment between the lower extremities of the radius and ulna. It is 
attached by its apex to a depression on the inner surface of the styloid 
process of the ulna, and by its base to the edge of the radius. This fibro- 
cartilage is lined upon its upper surface by a synovial membrane, which 
forms a duplicature between the radius and ulna, and is called the mem- 
brana sacciformis. By its lower surface it enters into the articulation of 
the wrist joint. 

Actions. — The movements taking place between the radius and the ulna 
are, the rotation of the former upon the latter ; rotation forwards being 
termed pronation, and rotation backwards supination. In these move- 
ments the head of the radius turns upon its own axis, within the orbicular 
ligament and the lesser sigmoid notch of the ulna ; while inferiorly the 

dius. 4. The external lateral ligament inserted inferiorly into (5) the orbicular liga- 
ment. 6. The posterior extremity of the orbicular ligament, spreading out at its insertion 
into the ulna. 7. The anterior ligament, scarcely apparent in this view of the articula- 
tion. 8. The posterior ligament, thrown into folds by the extension of the joint. 

* 1. Articular surface of olecranon process of the ulna. 2. Coronoid process. 3. Or- 
bicular ligament surrounding the neck of the radius. 



WRIST JOINT. 



155 



radius presents a concavity which moves upon the rounded head of the 
ulna. The movements of the radius are chiefly limited by the anterior 
and posterior inferior ligaments, hence these are not unfrequently ruptured 
in great muscular efforts. 

7. Wrist Joint. — The wrist is a ginglymoid articulation ; the articular 
surfaces entering into its formation being the radius and under surface of 
the triangular fibro-cartilage above, and the rounded surfaces of the 
scaphoid, semilunar, and cuneiform bone below ; its ligaments are four 
in number, — 

Anterior, Internal lateral, 

Posterior, External lateral. 

The anterior ligament is a broad and mem- Fi g . 90 * 

branous layer consisting of three fasciculi, which 
pass between the lower part of the radius and 
the scaphoid, semilunar, and cuneiform bone. 

The posterior ligament, also thin and loose, 
passes between the posterior surface of the ra- 
dius, and the posterior surface of the semilunar 
and cuneiform bone. 

The internal lateral ligament extends from 
the styloid process of the ulna to the cuneiform 
and pisiform bone. 

The external lateral ligament is attached by 
one extremity to the styloid process of the ra- 
dius, and by the other to the side of the scaphoid 
bone. The radial artery rests on this ligament 
as it passes backwards to the first metacarpal 
space. 

The synovial membrane of the wrist joint 
lines the under surface of the radius and inter- 
articular cartilage above, and the first row of 
bones of the carpus below. 

The relations of the wrist joint are the flexor 
and extensor tendons by which it is surrounded, and the radial and ulnar 
artery. 

Actions. — The movements of the wrist joint are flexion, extension, ad- 
duction, abduction, and circumduction. In these motions the articular 
surfaces glide upon each other. 

* The ligaments of the anterior aspect of the wrist and hand. 1. The lower part of 
the interosseous membrane. 2. The anterior inferior radio-ulnar ligament. 3. The an- 
terior ligament of the wrist joint. 4. Its external lateral ligament. 5. Its internal 
lateral ligament. 6. The palmar ligaments of the carpus. 7. The pisiform bone with 
its ligaments. 8. The ligaments connecting the second range of carpal bones with the 
metacarpal and the metacarpal with each other. 9. The capsular ligament of the carpo- 
metacarpal articulation of the thumb. 10. Anterior ligament of the metacarpo-pha- 
langeal articulation of the thumb. 11. One of the lateral ligaments of that articulation. 
12. Anterior ligament of the metacarpo-phalangeal articulation of the index finger; this 
ligament has been removed in the other fingers. 13. Lateral ligaments of the same 
articulation ; the corresponding ligaments are seen in the other articulations. 14. Trans- 
verse ligament connecting the heads of the metacarpal bones of the index and middle 
fingers; the same ligament is seen between the other fingers. 15. Anterior and one 
lateral ligament of the phalangeal articulation of the thumb. 16. Anterior and lateral 
ligaments of the phalangeal articulations of the index finger; the anterior ligaments are 
removed in the other fingers. 




156 CARPOMETACARPAL ARTICULATIONS. 

8. Articulations between the Carpal Bones. — These are amphi-arthrodial 
joints, with the exception of the conjoined head of the os magnum and 
unciforme, which is received into a cup formed by the scaphoid, semi- 
lunar, and cuneiform bone, and constitutes an enarthrosis. The ligaments 
are, 

Dorsal, Interosseous fibro-cartilage, 

Palmar, Anterior annular. 

The dorsal ligaments are ligamentous bands, that pass transversely and 
longitudinally from bone to bone, upon the dorsal surface of the carpus. 

The palmar ligaments are fasciculi of the same kind, but stronger than 
the dorsal, having the like disposition upon the palmar surface. 

The interosseous ligaments are fibro-cartilaginous lamellae situated be- 
tween the adjoining bones in each range : in the upper range they close 
the upper part of the spaces between the scaphoid, semilunar, and cunei- 
form bones ; in the lower range they are stronger than in the upper, and 
connect the os magnum on the one side to the unciforme, on the other to 
the trapezoides, and leave intervals through which the synovial membrane 
is continued to the bases of the metacarpal bones. 

The anterior annular ligament is a firm ligamentous band, which con- 
nects the bones of the two sides of the carpus. It is attached by one ex- 
tremity to the trapezium and scaphoid, and by the other to the unciform 
process o,f the unciforme and the base of the pisiform bone, and forms an 
arch over the anterior surface of the carpus, beneath which the tendons of 
the long flexors and the median nerve pass into the palm of the hand. 

The articulation of the pisiform bone with the cuneiform, is provided 
with a distinct synovial membrane, which is protected by fasciculi of liga- 
mentous fibres, forming a kind of capsule around the joint ; they are in- 
serted into the cuneiforme, unciforme, and base of the metacarpal bone of 
the little finger. 

Synovial Membranes. — There me Jive synovial membranes entering into 
the composition of the articulations of the carpus : — 

The first is situated between the lower end of the ulna and the interar- 
ticular fibro-cartilage ; it is called sacciform, from forming a sacculus be- 
tween the lateral articulation of the ulna with the radius. 

The second is situated between the lower surface of the radius and in- 
terarticular fibro-cartilage above, and the first range of bones of the carpus 
below. 

The third is the most extensive of the synovial membranes of the wrist ; 
it is situated between the two rows of carpal bones, and passes between 
the bones of the second range, to invest the carpal extremities of the four 
metacarpal bones of the fingers. 

The fourth is the synovial membrane of the articulation of the meta- 
carpal bone of the thumb with the trapezium. 

The fifth is situated between the pisiform and cuneiform bone. 

Actions. — Very little movement exists between the bones in each range, 
but more is permitted between the two ranges. The motions in the latter 
situation are those of flexion and extension. 

9. The Carpo-metacarpal Articulations. — The second row of bones of 
the carpus articulates with the metacarpal bones of the four fingers by 
dorsal and palmar ligaments; and the metacarpal bone of the thumb with 
the trapezium by a true capsular ligament. There is also in the carpo- 



METACARPO-PHALANGEAL ARTICULATION. 



157 



Fig. 91.* 




metacarpal articulation a thin interosseous band which passes trom the 
ulnar edge of the os magnum to the line of junction between the third 
and fourth metacarpal bones. 

The dorsal ligaments are strong fasciculi which pass from the second 
range of carpal to the metacarpal bones. 

The palmar ligaments are thin fasciculi arranged upon the same plan 
on the palmar surface. 

The synovial membrane is a continuation 
of the great synovial membrane of the two 
rows of carpal bones. 

The capsular ligament of the thumb is one 
of the three true capsular ligaments of the 
skeleton ; the other two being the shoulder 
joint and hip joint. The articulation has a 
proper synovial membrane. 

The metacarpal bones of the four fingers 
are firmly connected at their bases by means 
of dorsal and palmar ligaments, which ex- 
tend transversely from one bone to the other, 
and by interosseous ligaments, which pass 
between their contiguous surfaces. Their 
lateral articular facets are lined by a reflec- 
tion of the great synovial membrane of the 
two rows of carpal bones. 

Actions. — The movements of the metacarpal on the carpal bones are 
restricted to a slight degree of sliding motion, with the exception of the 
articulation of the metacarpal bone of the thumb with the trapezium. In 
the latter articulation, the movements are, flexion, extension, adduction, 
abduction, and circumduction. 

10. Metacarpo -phalangeal Articulation. — The metacarpo-phalangeal 
articulation is a ginglymoid joint ; its ligaments are four in number, — 

Anterior, Two lateral, Transverse. 

The anterior ligaments are thick and fibro-cartilaginous, and form part 
of the articulating surface of the joints. They are grooved externally for 
the lodgment of the flexor tendons, and by their internal aspect form part 
of the articular surface for the head of the metacarpal bone. 

The lateral ligaments are strong narrow fasciculi, holding the bones 
together at each side. 

The transverse ligaments are strong ligamentous bands, passing between 
the anterior ligaments, and connecting together the heads of the meta- 
carpal bones of the four fingers. 

* A diagram showing the disposition of the five synovial membranes of the wrist 
joint. 1. The sacciform membrane. 2. The second synovial membrane. 3, 3. The 
third, or large synovial membrane. 4. The synovial membrane between the pisiform 
bone and the cuneiforme. 5. The synovial membrane of the metacarpal articulation of 
the thumb. 6. The lower extremity of the radius. 7. The lower extremity of the ulna 
8. The interarticular fibro-cartilage. S. The scaphoid bone. L. The semilunare. 
C. The cuneiforme; the interosseous ligaments are seen passing between these three 
bones and separating the articulation of the wrist (2) from the articulation of the carpal 
bones (3). P. The pisiforme. T. The trapezium. 2T. The trapezoides. M. The os 
magnum. U. The unciforme ; interosseous ligaments are seen connecting the os mag- 
num with the trapezoides and unciforme. 9. The base of the metacarpal bone of the 
thumb. 10, 10. The bases of the other metacarpal bones. 

14 



158 HIP JOINT. 

The expansion of the extensor tendon over the back of the fingers takes 
the place of a posterior ligament. 

Actions. — This articulation admits of movement in four different direc- 
tions, viz. of flexion, extension, adduction, and abduction, the two latter 
being limited to a small extent. It is also capable of circumduction. 

11. Articulation of the Phalanges. — These articulations are ginglymoid 
joints . they are formed by three ligaments. 

Anterior, . Two lateral. 

The anterior ligament is firm and fibro-cartilaginous, and forms part of 
the articular surface for the head of the phalanges. Externally it is 
grooved for the reception of the flexor tendons. 

The lateral ligaments are very strong ; they are the principal bond of 
connexion between the bones. • 

The extensor tendon takes the place and performs the office of a poste- 
rior ligament. 

Actions. — The movements of the phalangeal joints are flexion and exten- 
sion, these movements being more extensive between the first and second 
phalanges than between the second and third. 

In connexion with the phalanges, it may be proper to examine certain 
fibrous bands termed thecce or vaginal ligaments, which serve to retain the 
tendons of the flexor muscles in their position upon the flat surface of their 
bones. These fibrous bands are attached at each side to the lateral mar- 
gins of the phalanges; they are thick in the interspaces of the joints, thin 
where the tendons lie upon the joints, and they are lined upon their inner 
surface by synovial membrane. 

LIGAMENTS OF THE LOWER EXTREMITY. 

The ligaments of the lower extremity, like those of the upper, may be 
arranged in the order of the joints to which they belong ; these are, the 

1. Hip joint. 

2. Knee joint. 

3. Articulation between the tibia and fibula. 

4. Ankle joint. 

5. Articulation of the tarsal bones. 

6. Tarso-metatarsal articulation. 

7. Metatarsophalangeal articulation. 

8. Articulation of the phalanges. 

1. Hip Joint. — The articulation of the head of the femur with the ace- 
tabulum constitutes an enarthrosis, or ball-and-socket joint. The articular 
surfaces are the cup-shaped cavity of the acetabulum and the rounded 
head of the femur ; the ligaments are five in number, viz. 

Capsular, Cotyloid, 

Ilio-femoral, Transverse. 

Teres, 

The capsular ligament (fig. 83, 8) is a strong ligamentous capsule, em- 
bracing the acetabulum superiorly, and inferiorly the neck of the femur, 
and connecting the two bones firmly together. It is much thicker upon 
the upper part of the joint, where more resistance is required, than upon 



HIP JOINT — KNEE JOINT. 159 

the under part, and extends further upon the neck of the femur on the 
anterior and superior than on the posterior and inferior side, being 
attached to the intertrochanteric line in front, to the base of the great tro- 
chanter above, and to the middle of the neck of the femur behind. 

The iliofemoral ligament (fig. 83, 9) is an accessory and radiating 
band, which descends obliquely from the anterior inferior spinous process 
of the ilium to the anterior intertrochanteric line, and strengthens the an- 
terior portion of the capsular ligament. 

The ligamentum teres (fig. 84, 7), triangular in shape, is attached by a 
round apex to the depression just below the middle of the head of the 
femur, and by its base, which divides into two fasciculi, into the borders 
of the notch of the acetabulum. It is formed by a fasciculus of fibres, of 
variable size, surrounded by synovial membrane ; sometimes the synovial 
membrane alone exists, or the ligament is w r holly absent. 

The cotyloid ligament (fig. 84, 6) is a prismoid cord of fibro-cartilage, 
attached around the margin of the acetabulum, and serving to deepen that 
cavity and protect its edges. It is much thicker upon the upper and pos- 
terior border of the acetabulum than in front, and consists of fibres which 
arise from the whole circumference of the brim, and interlace with each 
other at acute angles. 

The transverse ligament is a strong fasciculus of ligamentous fibres, 
continuous with the cotyloid ligament, and extended across the notch in 
the acetabulum. It converts the notch into a foramen, through which the 
articular branches of the internal circumflex and obturator arteries enter 
the joint. 

The fossa at the bottom of the acetabulum is filled by a mass of fat, 
covered by synovial membrane, which serves as an elastic cushion to the 
head of the bone during its movements. This was considered by Havers 
as the synovial gland. 

The synovial membrane is extensive ; it invests the head of the femur, 
and is continued around the ligamentum teres into the acetabulum, 
whence it is reflected upon the inner surface of the capsular ligament 
back to the head of the bone. 

The muscles immediately surrounding and in contact with the hip joint 
are, in front, the psoas and iliacus, which are separated from the capsular 
ligament by a large synovial bursa ; above, the short head of the rectus, 
and the gluteus minimus ; behind, the pyriformis, gemellus superior, obtu- 
rator internus, gemellus inferior, and quadratus femoris ; and to the inner 
side, the obturator externus and pectineus. 

Actions. — The movements of the hip joint are very extensive ; they are 
flexion, extension, adduction, abduction, circumduction, and rotation. 

2. Knee Joint. — The knee is a ginglymoid articulation of large size, 
and is provided with numerous ligaments ; they are thirteen in number. 

Anterior or ligamentum patellae, Transverse, 

Posterior or ligamentum posticum Two coronary, 

Winslowii, Ligamentum mucosum, ) ~ , 

Internal lateral, Ligamenta alaria, ^ false. 

Two external lateral, Two semilunar fibro-cartilages, 

Anterior or external crucial, Synovial membrane. 
Posterior or internal crucial, 

The first five are external to the articulation ; the next five are internal 



160 



KNEE JOINT. 



Fig. 92 * 




to the articulation ; the remaining three are mere folds of synovial mem- 
brane, and have no title to the name of ligaments. In addition to the 
ligaments, there are two fibro-cartilages, which are sometimes very erro- 
neously considered among the ligaments ; and a synovial membrane, 
which is still more improperly named the capsular ligament. 

The anterior ligament, or ligamentum patella, is the prolongation of 
the tendon of the extensor muscles of the thigh downwards to the tubercle 
of the tibia. It is, therefore, no ligament; and, as we have before stated, 
that the patella is simply a sesamoid bone, developed in the tendon of the 
extensor muscles for the defence of the front of the 
knee joint, the ligamentum patellae has no title to con- 
sideration, either as a ligament of the knee joint or as a 
ligament of the patella. 

A small bursa mucosa is situated between the liga- 
mentum patellae, near its insertion and the front of the 
tibia, and another of larger size is placed between the 
anterior surface of the patella and the fascia lata. 

The posterior ligament, ligamentum posticum Wins- 
lowii, is a broad expansion of ligamentous fibres which 
covers the whole of the posterior part of the joint. 
It is divisible into two lateral portions which invest the 
condyles of the femur, and a central portion which is 
depressed, and formed by the interlacement of fasciculi 
passing in different directions. The strongest of these 
fasciculi is that which is derived from the tendon of the semi-membranosus, 
and passes obliquely upwards and outwards, from the posterior part of 
the inner tuberosity of the tibia to the external condyle. Other accessory 
fasciculi are given off by the tendon of the popliteus and by the heads of 
the gastrocnemius. The middle portion of the ligament supports the 
popliteal artery and vein, and is perforated by several openings for the 
passage of branches of the azygos articular artery, and for the nerves of 
the joint. 

The internal lateral ligament is a broad and trapezoid layer of liga- 
mentous fibres, attached above to the tubercle on the internal condyle of 
the femur, and below to the side of the inner tuberosity of the tibia. It 
is crossed at its lower part by the tendons of the inner hamstring, from 
which it is separated by a synovial bursa, and it covers in the anterior 
slip of the semi-membranosus tendon and the inferior internal articular 
artery. 

External lateral ligaments. — The long external lateral ligament is a 
strong rounded cord, which descends from the posterior part of the 
tubercle upon the external condyle of the femur to the outer part of the 
head of the fibula. The short external lateral ligament is an irregular 
fasciculus situated behind the preceding, arising from the external condyle 
near the origin of the head of the gastrocnemius muscle, and inserted into 
the posterior part of the head of the fibula. It is firmly connected with 
the external semilunar fibro-cartilage, and appears principally intended to 
connect that cartilage with the fibula. The long external lateral ligament 

1. The tendon of the quadri- 



* An anterior view of the ligaments of the knee joint. 

-' e leg. 2. The patella. 3. '.., 
lsertion. 4, 4. The synovial membrane 



m* uuw-nui view vi me ligaments oi uie Kiit-e j — 
s extensor muscle of the leg. 2. The patella. 3. The anterior ligament, or liga- 

5. The internal 



mentnm patellae, near its insertion. 4, 4. The synovial membrane. 5. The internal 
lateral ligament. 6. The long external lateral ligament. 7. The anterior superior tibio- 
fibular ligament. 



KNEE JOINT. 



161 



Fig. 93.* 




is covered in by the tendon of the biceps, and has passing beneath it the 
tendon of origin of the popliteus muscle, and the inferior external articular 

artery. 

The true ligaments within the joint are the crucial, 
transverse, and coronary. 

The anterior, or external crucial ligament, arises 
from the depression upon the head of the tibia in front 
of the spinous process, and passes upwards and back- 
wards to be inserted into the inner surface of the outer 
condyle of the femur, as far as its posterior border. 
It is smaller than the posterior. 

The posterior, or internal crucial ligament, arises 
from the depression upon the head of the tibia, behind 
the spinous process, and passes upwards and forwards 
to be inserted into the inner condyle of the femur. 
This ligament is less oblique and larger than the an- 
terior. 

The transverse ligament is a small slip of fibres 
which extends transversely from the external semilunar fibro-cartilage, 
near its anterior extremity, to the anterior convexity of the internal 
cartilage. 

The coronary ligaments are the, short fibres by which the convex bor- 
ders of the semilunar cartilages are connected to the head of the tibia, and 
to the ligaments surrounding the joint. 

The semilunar Jibro-cartilages are two falciform plates of fibro-cartilage, 
situated around the margin of the head of the tibia, and serving to deepen 
the surface of articulation for the condyles of the femur. They are thick 
along their convex border, and thin and sharp along the concave edge. 

The internal semilunar fibro-cartilage forms an oval 
cup for the reception of the internal condyle ; it is 
connected by its convex border to the head of the 
tibia, and to the internal and posterior ligaments, by 
means of its coronary ligament ; and by its tw r o ex- 
tremities is firmly implanted into the depressions in 
front and behind the spinous process. The external 
semilunar fibro-cartilage bounds a circular fossa for 
the external condyle : it is connected by its Qonvex 
border with the head of the tibia, and to the external 
and posterior ligaments, by means of its coronary 
ligament ; by its two extremities it is inserted into 
the depression between the two projections which 
constitute the spinous process of the tibia. The two 
extremities of the external 
into the same fossa form almost 



Fig. 94.f 



cartilage 



being inserted 
a complete circle, 




* A posterior view of the ligaments of the knee joint. 1. The fasciculus of the liga 
mentum posticum Winslowii, which is derived from, 2. the tendon of the semi-mem- 
branosns muscle; the latter is cut short. 3. The process of the tendon which spreads 
out in the fascia of the popliteus muscle. 4. The process which is sent inwards be- 
neath the internal lateral ligament. 5. The posterior part of the internal lateral liga- 
ment. 6. The long external lateral ligament. 7. The short external lateral ligament. 
S. The tendon of the popliteus muscle cut short. 9. The posterior superior tibio-fibular 
igament. 
+ The right knee joint laid open from the front, in order to show the internal liga 
14* L 



162 



KNEE JOINT. 



and the cartilage being somewhat broader than the internal, nearly covers 
the articular surface of the tibia. The external semilunar fibro- cartilage 
besides giving off a fasciculus from its anterior border to constitute the 
transverse ligament, is continuous by some of its fibres with the extremity 
of the anterior crucial ligament ; posteriorly it divides into three slips ; 
one, a strong cOrd, ascends obliquely forwards and is inserted into the 
anterior part of the inner condyle in front of the posterior crucial ligament ; 
another is the fasciculus of insertion into the fossa of the spinous process ; 
and the third, of small size, is continuous with the posterior part of the 
anterior crucial ligament. 

The ligamentum mucosum is a slender conical process of synovial 
membrane enclosing a few ligamentous fibres w T hich proceed from the 
transverse ligament. It is connected, by its apex, with the anterior part 
of the condyloid notch, and by its base is lost in the mass of fat which 
projects into the joint beneath the patella. 

The alar ligaments are two fringed folds of sy- 
novial membrane, extending from the ligamentum 
mucosum, along the edges of the mass of fat to 
the sides of the patella. 

The synovial membrane of the knee joint is by 
far the most extensive in the skeleton. It invests 
the cartilaginous surfaces of the condyles of the 
femur, of the head of the tibia, and of the inner 
surface of the patella ; it covers both surfaces of 
the semilunar fibro-cartilages, and is reflected 
upon the crucial ligaments, and upOn the inner 
surface of the ligaments which form the circumfe- 
rence of the joint. On each side of the patella, it 
lines the tendinous aponeuroses of the vastus inter- 
num and vastus externus muscles, and forms a 
pouch of considerable size between the extensor 
tendon and the front of the femur. It also forms 

ments. 1. The cartilaginous surface of the lower extremity of the femur with its two 
condyles; the figure 5 rests upon the external; the figure 3 upon the internal condyle. 
2. The anterior crucial ligament. 3. The posterior crucial ligament. 4. Tlie transverse 
ligament. 5. The attachment of the ligamentum mucosum ; the rest has been removed. 
6. The internal semilunar fibro-cartilage. 7. The external rlbro-cartilage. 8. A part of 
the ligamentum patellae turned down. 9. The bursa, situated between the ligamentum 
patellae and the head of the tibia; it has been laid open. 10. The anterior superior 
tibio-fibular ligament. 11. The upper part of the interosseous membrane ; the opening 
above this membrane is for the passage of the anterior tibial artery. 

■f A longitudinal section of the left knee joint, showing the reflection of its synovial 
membrane. 1. The cancellous structure of the lower part of the femur. 2. The tendon 
of the extensor muscles of the leg. 3. The patella. 4. The ligamentum patellae. 5. 
The cancellous structure of the head of the tibia. 6. A bursa situated between the 
ligamentum patellae and the head of the tibia. 7. The mass of fat projecting into the 
cavity of the joint below the patella." ** The synovial membrane. 8. The pouch 
of synovial membrane which ascends between the tendon of the extensor muscles of 
the leg, and the front of the lower extremity of the femur. 9. One of the alar liga- 
ments ; the other has been removed with the opposite section. 10. The ligamentum 
mucosum left entire; the section being made to its inner side. 11. The anterior or 
external crucial ligament. 12. The posterior ligament. The scheme of the synovial 
membrane, which is here presented to the student, is divested of all unnecessary com- 
plications. It may be traced from the sacculus (at 8), along the inner surface of the 
patella ; then over the adipose mass (7). from which it throws off the mucous liga 
ment (10) ; then over the head of the tibia, forming a sheath to the crucial ligaments; 
then upwards along the posterior ligament and condyles of the femur to the saccular, 
whence its examination commenced. 




TIBIOFIBULAR ARTICULATIONS. 163 

the folds in the interior of the joint, called " ligamentum mucosum," and 
" ligamenta alaria." The superior pouch of the synovial membrane is 
supported and raised during the movements of the limb by a small muscle, 
the subcrureus, which is inserted into it. 

Between the ligamentum patellae and the synovial membrane is a con- 
siderable mass of fat, which presses the membrane towards the interior of 
the joint, and occupies the fossa between the two condyles. 

Besides the proper ligaments of the articulation, the joint is protected 
on its anterior part by the fascia lata, which is thicker upon the outer than 
upon the inner side, by a tendinous expansion from the vastus internus, 
and by some scattered ligamentous fibres which are inserted into the sides 
of the patella. 

Actions. — The knee joint* is one of the strongest of the articulations of 
the body, while at the same time it admits of the most perfect degree of 
movement in the directions of flexion and extension. During flexion, the 
articular surface of the tibia glides forward on the condyles of the femur, 
the lateral ligaments, the posterior, and the crucial ligaments are relaxed, 
while the ligamentum patellae being put upon the stretch, serves to press 
the adipose mass into the vacuity formed in the front of the joint. In 
extension, all the ligaments are put upon the stretch, with the exception 
of the ligamentum patellae. When the knee is semi-flexed, a partial de- 
gree of rotation is permitted. 

3. Articulation between the Tibia and Fibula. — The tibia and fibula are 
held firmly connected by means of seven ligaments, viz. 

Anterior, ) , Interosseous membrane, 

Posterior, \ ' Interosseous inferior, 

Anterior, ) » , Transverse. 

t, . • } below. 
Posterior, ) 

The anterior superior ligament is a strong fasciculus of parallel fibres, 
passing obliquely downwards and outwards from the inner tuberosity of 
the tibia, to the anterior surface of the head of the fibula. 

The posterior superior ligament is disposed in a similar manner upon 
the posterior surface of the joint. 

Within the articulation there is a distinct synovial membrane which is 
sometimes continuous with that of the knee joint. 

The interosseous membrane or superior interosseous ligament is a broad 
layer of aponeurotic fibres which pass obliquely downwards and outwards, 
from the sharp ridge on the tibia to the inner edge of the fibula, and are 
crossed at an acute angle by a few fibres passing in the opposite direction. 
The ligament is deficient above, leaving a considerable interval between 
the bones, through which the anterior tibial artery takes its course for- 
wards to the anterior aspect of the leg, and near its lower third there is 
an opening for the anterior peroneal artery and vein. 

The interosseous membrane is in relation, in front, with the tibialis 
anticus, extensor longus digitorum, and extensor proprius pollicis muscle, 
with the anterior tibial vessels and nerve, and with the anterior peroneal 
artery ; and behind, with the tibialis posticus, and flexor longus digitorum 
muscle, and with the posterior peroneal artery. 

The inferior interosseous ligament consists of short and strong fibres, 
which hold the bones firmly together inferiorly, where they are nearly in 



164 



ANKLE JOINT. 



contact. This articulation is so firm that the fibula is likely to be broken 
in the attempt to rupture the ligament. 

The anterior inferior ligament is a broad band, consisting of two fasci- 
culi of parallel fibres which pass obliquely across the anterior aspect of 
the articulation of the two bones at their inferior extremity, from the tibia 
to the fibula. 

The posterior inferior ligament (fig. 98, 2) is a similar band upon the 
posterior surface of the articulation. Both ligaments project somewhat 
below the margin of the bones, and serve to deepen the cavity of articu- 
lation for the astragalus. 

The transverse ligament (fig. 98, 3) is a narrow band of ligamentous 
fibres, continuous with the preceding, and passing transversely across the 
back of the ankle joint between the two malleoli. 

The synovial membrane of the inferior tibio-fibular articulation, is a 
duplicature of the synovial membrane of the ankle joint reflected upwards 
for a short distance between the two bones. 

Actions. — An obscure degree of movement exists between the tibia and 
fibula, which is principally calculated to enable the latter to resist injury, 
by yielding for a trifling extent to the pressure exerted. 

4. Ankle joint. — The ankle is a ginglymoid articulation ; the surfaces 
entering into its formation are the under surface of the tibia with its mal- 
leolus and the malleolus of the fibula, above, and the surface of the astra- 
galus with its two lateral facets, below. The ligaments are three in 
number : 

Anterior, Internal lateral, External lateral. 

The anterior ligament is a thin membranous layer, passing from the 
margin of the tibia to the astragalus in front of the articular surface. It 
is in relation, in front, with the extensor tendons of the great and lesser 
toes, with the tendons of the tibialis anticus and peroneus tertius, and with 
the anterior tibial vessels and nerve. Posteriorly it lies in contact with 
the extra- synovial adipose tissue and with the synovial membrane. 



Fig. 96* 



Fig. 97.f 





• An internal view of the ankle joint. 1. The internal malleolus of the tibia. 2, 2. 
Part of the astragalus : the rest is concealed by the ligaments. 3. The os calcis. 4. The 
scaphoid bone. 5. The internal cuneiform bone. G. The internal lateral or deltoid 
ligament. 7. The anterior ligament. 8. The tendo Achillis ; a small bursa is seen 
interposed between the tendon and the tuberosity of the os calcis. 

f An external view of the ankle-joint. 1. The tibia. 2. The external malleolus of 
the fibula. 3, 3. The astragalus. 4. The os calcis. 5. The cuboid bone. 6. The ante- 
rior fasciculus of the external lateral ligament attached to the astragalus. 7. Its middle 
fasciculus, attached to the os calcis. 8. Its posterior fasciculus, attached to the astra- 
galus. 9. The anterior ligament of the ankle. 



TARSAL ARTICULATIONS. 165 

The internal lateral or deltoid ligament is a triangular layer of fibres, 
attached superiorly by its apex to the internal malleolus, and inferiorly by 
an expanded base to the astragalus, os calcis, and scaphoid bone. Be- 
neath the superficial layer of this ligament is a much stronger and thicker 
fasciculus, which connects the apex of the internal malleolus with the side 
of the astragalus. 

This internal lateral ligament is covered in and partly concealed by the 
tendon of the tibialis posticus, and at its posterior part is in relation with 
the tendon of the flexor longus digitorum, and with that of the flexor 
longus pollicis. 

The external lateral ligament consists of three strong fasciculi, which 
proceed from the inner side of the external malleolus, and diverge in three 
different ejections. The anterior fasciculus passes forwards, and is 
attached to the astragalus ; the posterior, backwards, and is connected 
with the astragalus posteriorly ; and the middle, longer than the other two, 
descends to be inserted into the outer side of the os calcis. 

"It is the strong union of this bone," says Sir Astley Cooper, "with 
the tarsal bones, by means of the external lateral ligaments, which leads 
to its being more frequently fractured than dislocated." 

The transverse ligament of the tibia and fibula occupies the place of a 
posterior ligament. It is in relation, behind, with the posterior tibial ves- 
sels and nerve, and with the tendon of the tibialis posticus muscle ; and 
in front, with the extra-synovial adipose tissue, and synovial membrane. 

The Synovial membrane invests the cartilaginous surfaces of the tibia 
and fibula (sending a duplicate upwards between their lower ends), and 
the upper surface and two sides of the astragalus. It is then reflected 
upon the anterior and lateral ligaments, and upon the transverse ligament 
posteriorly. 

Actions. — The movements of the ankle joint are flexion and extension 
only, without lateral motion. 

5. Articulations of the Tarsal Bones. — The ligaments which connect 
the seven bones of the tarsus to each other are of three kinds, — 

Dorsal, Plantar, Interosseous. 

The dorsal ligaments are small fasciculi of parallel fibres, whrch pass 
from each bone to all the neighbouring bones with which it articulates. 
The only dorsal ligaments deserving of particular mention are, the external 
and posterior calcaneo-astragaloid, which, with the interosseous ligament, 
complete the articulation of the astragalus with the os calcis ; the superior 
and internal calcaneo-cuboid ligament. The internal calcaneo-cuboid and 
the superior calcaneo-scaphoid ligament, which are closely united pos- 
teriorly in the deep groove which intervenes between the astragalus and 
os calcis, separate anteriorly to reach their respective bones ; they form 
the principal bond of connexion between the first and second range of 
the bones of the foot. It is the division of this portion of these ligaments 
that demands the especial attention of the surgeon in performing Chopart's 
operation. 

The plantar ligaments have the same disposition on the plantar surface 
of the foot ; three of them, however, are of a large size, and have especial 
names, viz. the 

Calcaneo-scaphoid, Long calcaneo-cuboid, Short calcaneo-cuboid. 



166 



TARSAL ARTICULATIONS. 



Fig. 98.* 




The inferior calcaneo-scaphoid ligament is a broad and fibrocartilaginous 
band of ligament, which passes forwards from the anterior and inner bor- 
der of the os calcis and scaphoid bone. In addition to 
connecting the os calcis and scaphoid, it supports the 
astragalus, and forms part of the cavity in which the 
rounded head of the latter bone is received. It is lined 
upon its upper surface by the synovial membrane of the 
astragalo-scaphoid articulation. 

The firm connexion of the os calcis with the scaphoid 
bone, and the feebleness of the astragalo-scaphoid articu- 
lation, are conditions favourable to the occasional disloca- 
tion of the head of the astragalus. 

The long calcaneo- cuboid ligamentum, or longum plantce, 
is a long band of ligamentous fibres, which proceeds from 
the under surface of the os calcis to the rough surface on 
the under part of the cuboid bone, its fibres being con- 
tinued onwards to the bases of the third and fourth metatarsal bones. 

This ligament forms the inferior boundary of a canal in the cuboid 
bone, through which the tendon of the peroneus longus passes to its in- 
sertion in the base of the metatarsal bone of the great toe. 

The short calcaneo- cuboid, or ligamentum breve plantce, is situated 
nearer to the bones than the long plantar ligament, from which it is sepa- 
rated by adipose tissue ; it is broad and extensive, and ties the under 
surfaces of the os calcis and cuboid bone firmly together. 

The interosseous ligaments are five in number ; they are short and strong 
ligamentous fibres situated between adjoining bones, and firmly attached 
to their rough surfaces. One of these, the calcaneo-astragaloid, is lodged 
in the groove between the upper surface of the os calcis and the lower 
of the astragalus. It is large and very strong, consists of vertical and 
oblique fibres, and serves to unite the os calcis and astragalus solidly 
together. The second interosseous ligament, also very strong, is situated 
between the sides of the scaphoid and cuboid bone ; while the three re- 
maining interosseous ligaments connect strongly together the three cunei- 
form bones and the cuboid. 

The .synovial membranes of the tarsus are four in number ; one for the 
posterior calcaneo-astragaloid articulation ; a second, for the anterior cal- 
caneo-astragaloid and astragalo-scaphoid articulation. Occasionally an 
additional small synovial membrane is found in the anterior calcaneo- 
astragaloid joint ; a third, for the calcaneo-cuboid articulation ; and a 
fourth, the large tarsal synovial membrane, for the articulations between 
the scaphoid and three cuneiform bones, the cuneiform bones with each 
other, the external cuneiform bone with the cuboid, and the two external 
cuneiform bones with the bases of the second and third metatarsal bones. 
The prolongation which reaches the metatarsal bones passes forwards be- 
tween the internal and middle cuneiform bones. A small synovial mem- 
brane is sometimes met with between the contiguous surfaces of the 
scaphoid and cuboid bone. 

* A posterior view of the ankle joint. 1. The lower part of the interosseous mem- 
brane. 2. The posterior inferior ligament connecting the tibia and fibula. 3. The 
transverse ligament. 4. The internal lateral ligament. 5. The posterior fasciculus of 
the internal lateral ligament. 6. The middle fasciculus of the external lateral ligament. 
7. The synovial membrane of the ankle joint. 8. The os calcis. 



TARSO-METATARSAL ARTICULATION. 



167 



Actions. — The movements permitted by the articulation between the 
astragalus and os calcis, are a slight degree of gliding, in the directions 
forwards and backwards and laterally from side to side. The movements 
of the second range of tarsal bones is very trifling, being greater between 
the scaphoid and three cuneiform bones than in the other articulations. 
The movements occurring between the first and second range are the 
most considerable ; they are adduction and abduction, and, in a minor 
degree, flexion, which increases the arch of the foot, and extension, which 
flattens the arch. 

6. Tarso-metatarsal Articulation. — The ligaments of this articulation are, 



Dorsal, 



Plantar, 



Interosseous. 



Fig. 99. 



The dorsal ligaments connect the metatarsal to the tarsal bones, and 
the metatarsal bones with each other. The precise arrangement of these 
ligaments is of little importance, but it may be remarked, that the base 
of the second metatarsal b#ne, articulating with the three cuneiform bones, 
receives a ligamentous slip from each, while the rest, articulating with a 
single tarsal bone, receive only a single tarsal slip. 

The plantar ligaments have the same disposition on 
the plantar surface. 

The interosseous ligaments are situated between the 
bases of the metatarsal bones of the four lesser toes ; 
and also between the bases of the second and third 
metatarsal bones, and the internal and external cunei- 
form bones. 

The metatarsal bone of the second toe is implanted 
by its base between the internal and external cuneiform 
bones, and is the most strongly articulated of all the 
metatarsal bones. This disposition must be recollected 
in amputation at the tarso-metatarsal articulation. 

The synovial membranes of this articulation are three il 
in number : one for the metatarsal bone of the great 
toe ; one for the second and third metatarsal bones, 
which is continuous with the great tarsal synovial mem- 
brane ; and one for the fourth and fifth metatarsal 
bones. 

Actions. — The movements of the metatarsal bones 
upon the tarsal, and upon each other, are very slight ; 
they are such only as contribute to the strength of the 
foot by permitting of a certain degree of yielding to opposing forces. 

7. Metatarsal-phalangeal Articulation. — The ligaments of this articula- 
tion, like those of the articulation between the first phalanges and meta- 
carpal bones of the hand, are. 

Anterior or plantar, Two lateral, Transverse. 

* The ligaments of the sole of the foot. 1. The os calcis. 2. The astragalus. 3. The 
tuberosity of the scaphoid bone. 4. The long calcaneocuboid ligament. 5. Part of the 
short calcaneo-cuboid ligament. 6. The calcaneo-scaphoid ligament. 7. The plantar 
tarsal ligaments. 8, 8. The tendon of the peroneus longus muscle. 9. 9. Plantar tarso- 
metatarsal ligaments. 10. Plantar ligament of the metatarsophalangeal articulation of 
the great toe; the same ligament is seen upon the other toes. 11. Lateral ligaments of 
the metatarso-phalangeal articulation. 12. Transverse ligament. 13. The lateral liga- 
ments of the phalanges of the great toe ; the same ligaments are seen upon the other 
toes. 




168 STRUCTURE OF MUSCLE. 

The anterior or plantar ligaments are thick and fibrocartilaginous, and 
form part of the articulating surface of the joint. 

The lateral ligaments are short and very strong, and situated on each 
side of the joints. 

The transverse ligaments are strong bands, which pass transversely be- 
tween the anterior ligaments. 

The expansion of the extensor tendon supplies the place of a dorsal 
ligament. 

Actions. — The movements of the first phalanges upon the rounded 
heads of the metatarsal bones, are ^/ferioTi, extension, adduction and abduc- 
tion. 

8. Articulation of the Phalanges. — The ligaments of the phalanges are 
the same as those of the fingers, and have the same disposition; their 
actions are also similar. They are, 

Anterior or plantar, Two lateral. 



CHAPTER IV. 

ON THE MUSCLES. 



Muscles are the moving organs, of the animal frame ; they constitute 
by their size and number the great bulk of the body, upon which they 
bestow form and symmetry. In the limbs they are situated around the 
bones, which they invest and defend, while they form to some of the joints 
a principal protection. In the trunk they are spread out to enclose cavi- 
ties, and constitute a defensive wall capable of yielding to internal pressure, 
and again returning to its original position. 

Their colour presents the deep red which is characteristic of flesh, and 
their form is variously modified, to execute the varied range of movements 
which they are required to effect. 

Muscle is composed of a number of parallel fibres placed side by side, 
and supported and held together by a delicate web of areolar tissue ; so 
that, if it were possible to remove the muscular substance, we should have 
remaining a beautiful reticular framework, possessing the exact form and 
size of the muscle without its colour and solidity. Towards the extremity 
of the organ the muscular fibre ceases, and the areolar structure becomes 
aggregated and modified, so as to constitute those glistening fibres and 
cords by which the muscle is tied to the surface of bone, and which are 
called tendons. Almost every muscle in the body is connected with bone, 
either by tendinous fibres, or by an aggregation of those fibres constituting 
a tendon ; and the union is so firm, that, under extreme violence, the 
bone itself rather breaks than permits of the separation of the tendon from 
its attachment. In the broad muscles the tendon is spread so as to form 
an expansion, called aponeurosis (d^o, longe ; vetJgov,* nervus — a nerve 
widely spread out). 

Muscles present various modifications in the arrangement of their fibres 
in relation to their tendinous structure. Sometimes they are completely 

• The ancients named ull the white fibres of the body vcvpa ; the term has since been 
limited to the nerves. 



STRUCTURE OF MUSCLE. 169 

longitudinal, and terminate at each extremity in tendon, the entire muscle 
being fusiform in its shape ; in other situations they are disposed like the 
rays of a fan, converging to a tendinous point, as the temporal, pectoral, 
glutei, &c, and constitute a radiate muscle. Again, they are pe?iniform, 
converging like the plumes of a pen to one side of a tendon, which runs 
the whole length of the muscle as in the peronei ; or bipenniform, con- 
verging to both sides of the tendon. In other muscles the fibres pass 
obliquely from the surface of a tendinous expansion spread out on one 
side, to that of another extended on the opposite side, as in the semi- 
membranosus ; or, they are composed of penniform or bipenniform fasci- 
culi as in the deltoid, and constitute a compound muscle. 

The nomenclature of the muscles is defective and confused, and is 
generally derived from some prominent character which each muscle pre- 
sents ; thus, some are named from their situation, as the tibialis, peroneus ; 
others from their uses, as the flexors, extensors, adductors, abductors, le- 
vators, tensors, &c. Some again from their form, as the trapezius, trian- 
gularis, deltoid, &c. ; and others from their direction, as the rectus, 
obliquus, trartsversalis, &c. Certain muscles have received names ex- 
pressive of their attachments, as the sterno-mastoid, sterno-hyoid, &c. ; and 
others, of their divisions, as the biceps, triceps, digastricus, complexus, &c. 

In the description of a muscle Ave express its attachment by the words 
" origin" and " insertion ;" the term origin is generally applied to the 
more fixed or central attachment, or to the point towards which the motion 
is directed, while insertion is assigned to the more movable point, or to 
that most distant from the centre ; but there are many exceptions to this 
principle,, and as many muscles pull equally by both extremities, the use 
of such terms must be regarded as purely arbitrary. 

In structure, muscle is composed of bundles of fibres of variable size 
called fasciculi, which are enclosed in a cellular membranous investment 
or sheath, and the latter is continuous with the cellular framework of the 
fibres. Each fasciculus is composed of a number of smaller bundles, and 
these of single fibres, which, from their minute size and independent ap- 
pearance, have been distinguished by the name of ultimate fibres. The 
ultimate fibre is found by microscopic investigation to be itself a fasciculus 
(ultimate fasciculus), made up of a number of ultimate fibrils enclosed in 
a delicate sheath or myolemma.* Two kinds of ultimate muscular fibre 
exist in the animal economy ; viz., that of voluntary or animal life, and 
that of involuntary or organic life. 

The ultimate fibre of animal life is known by its size, by its uniformity 
of calibre, and especially by the very beautiful transverse markings which 
occur at short and regular distances throughout its whole extent. It also 
presents other markings or striae, having a longitudinal direction, which 
indicate the existence of fibrillar within its myolemma. The myolemma, 
or investing sheath of the ultimate fibre, is thin, structureless and trans- 
parent. 

* In the summer of 1836, while engaged with Dr. Jones Quain in the examination of 
the animal tissues with a simple dissecting microscope, constructed by Powell, I first 
saw that the ultimate fibre of muscle was invested by a proper sheath, for which I pro- 
posed the term " Myolemma ;" a term which was adopted by Dr. Quain in the fourth 
edition of his " Elements of Anatomy." We at that time believed that the transverse 
folding of that sheath gave rise to the appearance of transverse striae, an opinion which 
subsequent examinations proved to be incorrect. Mr. Bowman employs the term " Sar- 
colemma," as synonymous with Myolemma. 

15 



170 



STRUCTURE OF MUSCLE. 



According to Mr. Bowman* the ultimate fibres are polygonal in shape 
[fig. 100] from mutual pressure. They are also variable in their size, not 
merely in different classes and genera of animals and different sexes, but 
even in the same muscle. For example, the average diameter of the ulti- 
mate fibre in the human female is ? |j, while that of the male is ^| f , the 
average of both being ? fo. The largest fibres are met with in fishes, in 
which animals they average 2 ^ 2 5 tne next largest are found in man, while 
in other classes they range in the following order: — insects ? fg ; reptiles 
? £ ? ; mammalia 5 & T ; birds H £ 7 . 

The ultimate fibrils of animal life, according to Mr. Bowman, are beaded 
filaments consisting of a regular succession of segments and constrictions, 
the latter being narrower than the former, and the component substance 
probably less dense. 



Fig. lOO.f 



Fig, 1014 





An ultimate fibre consists of a bundle of these fibrils, which are so dis- 
posed that all the segments and all the constrictions correspond, and in 
this manner give rise to the alternate light and dark lines of the transverse 
striae. The fibrils are connected together with very different degrees of 
closeness in different animals ; in man they are but slightly adherent, and 
distinct longitudinal lines of junction may be observed between them; 
they also separate very easily when macerated for some time. Besides 
the more usual separation of the ultimate fibre into fibrils, it breaks when 
stretched, into transverse sections [fig. 101,] corresponding with the dark 
line of the striae, and consequently with the constrictions of the fibrillar 
When this division occurs with the greatest facility, the longitudinal lines 
are indistinct, or scarcely perceptible. " In fact," says Mr. Bowman, 
" the primitive fasciculus seems to consist of primitive component segments 
or particles, arranged so as to form, in one sense, fibrillae, and in another 
sense, discs ; and which of these two may happen to present itself to the 
observer, will depend on the amount of adhesion, endways or sideways, 
existing between the segments. Generally, in a recent fasciculus, there 
are transverse striae, showing divisions into discs, and longitudinal striae, 
marking its composition by fibrillse." 

Mr. Bowman has observed that in the substance of the ultimate fibre 
there exist minute " oval or circular discs, frequently concave on one or 

* On the Minute Structure and Movements of Voluntary Muscle. By Wm, Bowman, 
Esq. From the Philosophical Transactions for 1840. 

f Transverse section of ultimate fibres of the biceps, copied from the illustrations to 
Mr. Bowman's paper. In this figure the polygonal form of the fibres is seen, and their 
composition of ultimate fibrils-. 

* An ultimate fibre, in which the transverse splitting into discs, in the direction of the 
constrictions of the ultimate fibrils is seen. From Mr. Bowman's paper. 



STRUCTURE OF MUSCLE. 



171 



Fig. 102 * 




j.0 



Fig. 103.1 



>l 



both surfaces, and containing, somewhere near the centre, one, two, or 
iiree minute dots or granules." Occasionally they are seen to present ir- 
regularities of form, which Mr. Bowman is inclined to regard as accidental. 
They are situated between, and are connected with the fibrils, and are 
distributed in pretty equal numbers through the fibre. These corpuscles 
are the nuclei of the nucleated cells from which the 
muscular fibre was originally developed. From ob- 
serving, however, that their " absolute number is far 
greater in the adult than in the foetus, while their 
number, relatively to the bulk of the fasciculi, at these 
two epochs, remains nearly the same," Mr. Bowman 
regards it as certain, that " during development, and 
subsequently, a further and successive deposit of cor- 
puscles" takes place. The corpuscles are brought 
into view only when the muscular fibre is acted upon 
by a solution of " one of the milder acids, as the citric." 
According to my own investigations,! the ultimate 
fibril of animal life is cylindrical when isolated, and 
probably polygonal from pressure when forming part 
of an ultimate fibre or fasciculus. It measures in 
diameter ^otjuo" °f an mcn > and is composed of a suc- 
cession of cells connected by their flat surfaces. The 
cells are filled with a transparent substance, which I 
have termed myoline. The myoline differs in density 
in different cells, and from this circumstance bestows 
a peculiarity of character on certain of the cells ; for 
example, when a fibril in its passive state is examined, 
there will be seen a series of dark oblong bodies se- 
parated by light spaces of equal length ; now the dark 
bodies are each composed of a pair of cells contain- 
ing the densest form of myoline, and are hence highly refractive while the 
transparent spaces are constituted by a pair of cells containing a more 
fluid myoline. When the fibrils are collected together so as to form an 
ultimate fibre or fasciculus, the appearance of the cell is altered ; those 
which look dark in the single fibril, that is, the most refractive, being 

* Mass of ultimate fibres from the pectoralis major of the human fcetus, at nine 
months. These fibres have been immersed in a solution of tartaric acid, and their 
"numerous corpuscles, turned in various directions, some presenting nucleoli," are 
shown. From Mr. Bowman's paper. 

f These were made on dissections of fresh human muscle, prepared with great care 
by Mr. Lealand, partner of the eminent optician, Mr. Powell. 

$ Structure of the ultimate muscular fibril and fibre of animal life. 

a. An ultimate muscular fibril in the state of partial contraction. 

b. A similar fibril in the state of ordinary relaxation. This fibril measured ^-- 5ff 
of an inch in diameter. 20 ° 

c. A similar fibril put upon the stretch, and measuring yg--^ of an inch in diameter. 
b. Plan of a portion of an ultimate fibre, showing the manner in which the transverse 

strise are produced by the collocation of the fibrils. 

Nos. 1, 1. The pair of highly-refractive cells; they form the dark parts of the single 
fibrils, but the bright parts of the fibre b. In the stretched fibril c, each cell has the 
appearance of being double. 2, 2. The pair of less refractive cells, light in the single 
fibrils, but forming the shaded stria in b. The transverse septum between these cells 
is very conspicuous ; and in c two other septa are seen to exist, making the number of 
transparent cells four. In b, the tier of cells immediately above the dark tier is partially 
illumined from the obliquity of the light. 



E 



172 



STRUCTURE OF MUSCLE. 



Fisr. 104.* 



ranged side by side, constitute the bright band ; while the transparent 
cells of the single fibril are the shaded stria of the fibre. 

When the ultimate fibril is very much stretched, the two highly-refrac- 
tive cells appear each to be double, while the transparent space is evidently 
composed of four cells. 

The ultimate fibre of organic life (Fig. 104, 4, 5) is a simple homoge- 
neous filament, much smaller than the fibre of animal life, flat, and with- 
out transverse markings. Besides these characters, there may generally 
be seen a dark line or several dark points in its interior, and not unfre- 
quently the entire fibre appears enlarged at irregular distances. These 
appearances are due to the presence of the unobliterated nuclei of cells 
from which the fibre was originally developed. The fibres of organic life 
are collected into fasciculi of various size, and are held together by dark 
nuclear fibres, similar to those which bind the fasciculi of fibrous tissue 

IP- 134.) 

The development of muscular fibre is 

effected by means of the formation of 
nucleated cells out of an original blas- 
tema, and the conversion of those cells, 
by a process already described (p. 46), 
into the tubuli of ultimate fibres, while 
their contents, by a subsequent deve- 
lopmental action, are transferred into 
ultimate fibrils. According to this view 
the cell membranes constitute the myo- 
lemma, and the contents of the cell are 
a blastema out of which new cells are 
formed. 

The disposition of these latter cells, in the production of fibrillse, is 
probably much more simple than has hitherto been, conceived. In the 
muscular fibre of organic life, the process would seem to stop short of the 
formation of fibrillae, the cells being accumulated without apparent order. 
The corpuscles, observed by Mr. Bowman, in fetal muscle (fig. 102), and 
the nodosities of organic fibre, are obviously undeveloped cells and nuclei. 
Muscles are divided into two great classes, voluntary and involuntary, 
to which may be added, as an intermediate and connecting link, the 
muscle of the vascular system, the heart. 

The voluntary, or system of animal life, is developed from the external 
or serous layer of the germinal membrane, and comprehends the whole 
of the muscles of the limbs and of the trunk. The involuntary, or organic 
system, is developed from the internal or mucous layer, and constitutes 
the thin muscular structure of the intestinal canal, bladder, and internal 

* 1. A muscular fibre of animal life enclosed -in its myolemma; the transverse and 
longitudinal striae are seen. 

2. An ultimate fibril of muscular fibre of animal life, according to Mr. Bowman. 

3. A muscular fibre of animal life, similar to 1, but more highly magnified. Its myo- 
lemma is so thin and transparent, as to permit the ultimate fibrils to be seen through. 
The true nature of the longitudinal striae is seen in this fibre, as well as the mode of 
formation of the transverse striae. 

4. A muscular fibre of organic life, from the urinary bladder, magnified 600 times, 
linear measure. Two of the nuclei are seen. 

5. A muscular fibre of organic life, from the stomach, magnified 600 times. The 
diameter of this and of the preceding fibre, midway between the nuclei, was ^ 6 
of an inch. 




MUSCLES OF THE HEAD AND NECK. 173 

organs of generation. At the commencement of the alimentary canal in 
the oesophagus, and near its termination in the rectum, the muscular coat 
is formed by a blending of the fibres of both classes. The heart is deve- 
loped from the middle, or vascular layer of the germinal membrane ; and 
although involuntary in its action, is composed of ultimate fibres, having 
the transverse striae of the muscle of animal life. 

The muscles may be arranged in conformity with the general division 
of the body into, — 1. Those of the head and neck. 2. Those of the 
trunk. 3. Those of the upper extremity. 4. Those of the lower ex- 
tremity. 

MUSCLES OF THE HEAD AND NECK. 

The muscles of the head and neck admit of a subdivision into those of 
the head and face, and those of the neck. 

Muscles of the Head and Face. — These muscles may be divided into 
groups, corresponding with the natural regions of the head and face ; the 
groups are eight in number, viz. — 

1. Cranial group. ' 5. Superior labial group. 

2. Orbital group. 6. Inferior labial group. 

3. Ocular group. 7. Maxillary group. 

4. Nasal group. 8. Auricular group. 

The muscles of each of these groups may be thus arranged — 

1. Cranial group. Levator lab ii superioris proprius, 
Occipito-frontalis. Levator anguli oris, 

Zygomaticus major, 

2. Orbital group. Zygomaticus minor, 
Orbicularis palpebrarum, Depressor labii superioris alaeque 
Corrugator supercilii, nasi. 

Tensor tarsi. 

6. Inferior labial group. 

3. Ocular group. . . . ■ m 
T , , (Orbicularis oris). 
Levator palpebrae, Depressor labii mferioris, 
Kectus superior, r\ i- • 

t, , . K • ' Depressor anaruli oris, 

Kectus interior, T r , i u- • r • • 

■n ' Levator- labii mferioris. 

Kectus internus, 

Rectus externus, 7. Maxillary group. 

Obliquus superior, , T 

r^uv • r • Masseter, 

Obliquus inferior. ^ v 

1 I emporalis, 

4. Masai group. Buccinator, 

Pyramidalis nasi, Pterygoideus externus, 

Compressor nasi, Pterygoideus internus. 

Dilatator naris. a • ? 

o. Jluncular group. 

5. Superior labial group. Attollens aurem, 
(Orbicularis oris), Attrahens aurem, 
Levator labii superioris alaeque nasi, Retrahens aurem. 

* The orbicularis oris, from encircling the mouth, belongs necessarily to both the 
superior and inferior labial regions; it is therefore enclosed within parentheses in 
both. 

15* 



174 



CRANIAL GROUP. 



Fig. 105.* 




1. Cranial group. — Occipito-frontalis. 

Dissection. — The occipito-frontalis is to be dissected by making a lon- 
gitudinal incision along the vertex of the 
head, from the tubercle on the occipital 
bone to the root of the nose; and a 
second incision along the forehead and 
around the side of the head, to join the 
two extremities of the preceding. Dis- 
sect the integument and superficial fascia 
carefully outwards, beginning at the an- 
terior angle of the flap, where the mus- 
cular fibres are thickest, and remove it 
altogether. This dissection requires care ; 
for the muscle is very thin, and, without 
attention, would be raised with the in- 
tegument. There is no deep fascia on 
the face and head, nor is it required ; for 
here the muscles are closely applied 
against the bones upon which they de- 
pend for support, whilst in the extremities 
the support is derived from the dense 
layer of fascia by which they are invested, and which forms for each a 
distinct sheath. 

The Occipito-frontalis is a broad musculo-aponeurotic layer, which 
covers the whole of the side of the vertex of the skull, from the occiput to 
the eyebrow. It arises by tendinous fibres from the outer two-thirds of 
the superior curved line of the occipital, and from the mastoid portion of 
the temporal bone. Its insertion takes place by means of the blending of 
the fibres of its anterior portion with those of the orbicularis palpebrarum, 
corrugator supercilii, levator labii superioris alseque nasi, and pyramidalis 
nasi. The muscle is fleshy in front over the frontal bone and behind over 
the occipital, the two portions being connected by a broad aponeurosis. 
The two muscles, together with their aponeurosis, cover the whole of the 
vertex of the skull, hence their designation galea capitis ; they are loosely 
adherent to the pericranium, but very closely to the integument, particu- 
larly over the forehead. 

Relations. — This muscle is in relation by its external surface from be- 
fore backwards, with the frontal and supra-orbital vessels, the supra-orbital 
and facial nerve, the temporal vessels and nerve, the occipital vessels and 

* The muscles of the head and face. 1. The frontal portion of the occipito-frontalis. 
2. Its occipital portion. 3. Its aponeurosis. 4. The orbicularis palpebrarum, which 
conceals the corrugator supercilii and tensor tarsi. 5. The pyramidalis nasi. 0. The 
compressor nasi. 7. The orbicularis oris. 8. The levator labii superioris ala?que nasi, 
the adjoining fasciculus between numbers 8 and 9 is the labial portion of the muscle 
9. The levator labii superioris proprius ; the lower part of the levator anguli oris is seen 
between the muscles 10 and 11. 10. The zygomaticus minor. 11. The zygomatk-us 
major. 12. The depressor labii inferioris. 13. The depressor anguli oris. 14. The 
levator labii inferioris. 15. The superficial portion of the masseter. 16. Its deep por- 
tion. 17. The attrahens aurem. 18. The buccinator. 19. The attollens aurem. 20. 
The temporal fascia which covers in the temporal muscle. 21. The retrahens aurem 
22. The anterior belly of the digastrieus muscle; the tendon is seen passing through 
its aponeurotic pulley. 23. The stylo-hyoid muscle, pierced by the posterior belly of the 
digastricus. 24. The mylo-hyoideus muscle. 25. The upper part of the sterno-mastoid. 
26. The upper part of the trapezius. The muscle between 25 and 26 is the splenius. 



ORBITAL GROUP. 175 

nerves, and with the integument, to which it is very closely adherent. Its 
under surface is attached to the pericranium by a loose areolar tissue 
which admits of considerable movement. 

Actions. — To raise the eyebrows, thereby throwing the integument of 
the forehead into transverse wrinkles. Some persons have the power of 
moving the entire scalp upon the pericranium by means of these muscles. 

2. Orbital group. — Orbicularis palpebrarum, 
Corrugator supercilii, 
Tensor tarsi. 

Dissection. — The dissection of the face is to be effected by continuing 
the longitudinal incision of the vertex of the previous dissection onwards 
to the tip of the nose, and thence downwards to the margin of the upper 
lip ; then carry an incision along the margin of the lip to the angle of the 
mouth, and transversely across the face to the angle of the lower jaw. 
Lastly, divide the integument in front of the external ear upwards to the 
transverse incision which was made for exposing the occipito-frontalis. 
Dissect the integument and superficial fascia carefully from the whole of 
the region included by these incisions, and the present with the two fol- 
lowing groups of muscles will be brought into view. 

The Orbicularis Palpebrarum is a sphincter muscle, surrounding the 
orbit and eyelids. It arises from the internal angular process of the frontal 
bone, from the nasal process of the superior maxillary, and from a short 
tendon (tendo oculi) which extends between the nasal process of the supe- 
rior maxillary bone, and the inner extremities of the tarsal cartilages of the 
eyelids. The fibres encircle the orbit and eyelids, forming a broad and 
thin muscular plane, which is inserted into the lower border of the tendo 
oculi, and into the nasal process of the superior maxillary bone. Upon 
the eyelids the fibres are thin and pale, and possess an involuntary action. 
The tendo oculi, in addition to its insertion into the nasal process of the 
superior maxillary bone, sends a process inwards which expands over the 
lachrymal sac, and is attached to the ridge of the lachrymal bone : this is 
the reflected aponeurosis of the tendo oculi. 

Relations. — By its superficial surface it is closely adherent to the integu- 
ment from which it is separated over the eyelids by a loose areolar tissue. 
By its deep surface it lies in contact above with the upper border of the 
orbit, with the corrugator supercilii muscle, and with the frontal and 
supra-orbital vessels and supra-orbital nerve ; below, with the lachrymal 
sac, with the origins of the levator labii superioris alaeque nasi, levator 
labii superioris proprius, zygomaticus major and minor muscles, and 
malar bone ; and externally with the temporal fascia. Upon the eyelids 
it is in relation with the broad tarsal ligament and tarsal cartilages, and 
by its upper border gives attachment to the occipito-frontalis muscle. 

The Corrugator Supercilii is a small narrow and pointed muscle, 
situated immediately above the orbit and beneath the upper segment of 
the orbicularis palpebrarum muscle. It arises from the inner extremity 
of the superciliary ridge, and is inserted into the under surface of the orbi- 
cularis palpebrarum at a point corresponding with the middle of the super- 
ciliary arch. 

Relations. — By its superficial surface with the pyramidalis nasi, occipito- 
frontalis and orbicularis palpebrarum muscle ; and by its deep surface, 
with the supra-orbital vessels and nerve. 



176 



OCULAR GROUP. 



Fig. I06.f 




The Tensor Tarsi (Horner's* muscle) is a thin plane of muscular 
fibres, about three lines in breadth and six in length. It is best dissected 

by separating the eyelids from the eye, 
and turning them over the nose without 
disturbing the tendo oculi ; then dissect 
away the small fold of mucous membrane 
called plica semilunaris, and some loose 
cellular tissue under which the muscle is 
concealed. It arises from the orbital sur- 
face of the lachrymal bone, and passing 
across the lachrymal sac divides into two 
slips, which* are inserted into the lachry- 
mal canals as far as the puncta. 
Actions. — The palpebral portion of the orbicularis acts involuntarily 
in closing the lids, and from the greater curve of the upper lid, upon that 
principally. The entire muscle acts as a sphincter, drawing at the same 
time, by means of its osseous attachment, the integument and lids inwards 
towards the nose. The corrugatores superciliorum draw the eyebrows 
downwards and inwards, and produce the vertical wrinkles of the fore- 
head. The tensor tarsi, or lachrymal muscle, draws the extremities of 
the lachrymal canals inwards, so as to place the puncta in the best posi- 
tion for receiving the tears. It serves also to keep the lids in relation 
with the surface of the eye, and compresses the lachrymal sac. Dr. Hor- 
ner is acquainted with two persons who have the voluntary power of 
drawing the lids inwards by these muscles so as to bury the puncta in the 
angle of the eye. 

3. Ocular group. — Levator palpebrse, 
Rectus superior, 
Rectus inferior, 
Rectus internus, 
Rectus externus, 
Obliquus superior, 
Obliquus inferior. 

Dissection. — To open the orbit (the 
calvarium and brain having been re- 
moved) the frontal bone must be sawn 
through at the inner extremity of the 
orbital ridge, and, externally, at its 
outer extremity. The roof of the or- 
bit may then be comminuted by a few 
light blows with the hammer ; a pro- 
cess easily accomplished, on account 
of the thinness of the orbital plate of 
the frontal bone and lesser wins: of the 

* W. E. Horner, M.D., Professor of Anatomy in the University of Pennsylvania. The 
notice of this muscle is contained in a work published in Philadelphia in 1827, entitled 
«' Lessons in Practical Anatomy." 

j A view of the tensor tarsi muscle. 1, 1. Bony margins of the orbit. 2. Opening 
between the eyelids. 3. Internal face of the orbit. 4. Origin of the tensor tarsi. 5, 5. 
Insertion into the neighbourhood of the puncta lachrymalis. 

* The muscles of the eyeball ; the view is taken from the outer side of the right orbit. 
1. A small fragment of the sphenoid bone around the entrance of the optic nerve into 
the orbit. 2. The optic nerve. 3. The globe of the eye. 4. The levator palpebrae 



Fig. 1074 




RECTUS EXTERNUS. 177 

sphenoid. The superciliary portion of the orbit may now be driven for- 
wards by a smart blow, and the external angular process and external 
wall of the orbit outwards in the same manner ; the broken fragments of 
the roof of the orbit should then be removed. By this means the perios- 
teum will be exposed unbroken and undisturbed. Remove the periosteum 
from the whole of the upper surface of the exposed orbit, and examine the 
parts beneath. 

The Levator Palpebrje is a long, thin, and triangular muscle ; situated 
in the upper part of the orbit on the middle line ; it arises from the upper 
margin of the optic foramen, and from the fibrous sheath of the optic nerve, 
and is inserted into the upper border of the superior tarsal cartilage. 

Relations. — By its upper surface with the fourth nerve, the supra-orbital 
nerve and artery, the periosteum of the orbit, and in front with the inner 
surface of the broad tarsal ligament. By its under surface it rests upon 
the superior rectus muscle, and the globe of the eye ; it receives its nerve 
and artery by this aspect, and in front is covered for a short distance by 
the conjunctiva. 

The Rectus Superior (attollens) arises from the upper margin of the 
optic foramen, and from the fibrous sheath of the optic nerve, and is in- 
serted into the upper surface of the globe of the eye at a point somewhat 
more than three lines from the margin of the cornea. 

Relations. — By its upper surface with the levator palpebrse muscle ; by 
the under surface with the optic nerve, the ophthalmic artery and nasal 
nerve, from which it is separated by a layer of fascia and by the adipose 
tissue of the orbit, and in front with the globe of the eye, the tendon of the 
superior oblique muscle being interposed. 

The Rectus Inferior (depressor) arises from the inferior margin of the 
optic foramen by a tendon (ligament of Zinn) which is common to it, the 
internal and the external rectus, and from the fibrous sheath of the optic 
nerve ; it is inserted into the inferior surface of the globe of the eye at a 
little more than two lines from the margin of the cornea. 

Relations. — By its upper surface with the optic nerve, the inferior oblique 
branch of the third nerve, the adipose tissue of the orbit, and the under 
surface of the globe of the eye. By its under surface with the periosteum 
of the floor of the orbit, and with the inferior oblique muscle. 

The Rectus Internus (adductor), the thickest and shortest of the 
straight muscles, arises from the common tendon, and from the fibrous 
sheath of the optic nerve ; and is inserted into the inner surface of the 
globe of the eye at two lines from the margin of the cornea. 

Relations. — By its internal surface with the optic nerve, the adipose 
tissue of the orbit and the eyeball. By its outer surface with the perios- 
teum of the orbit ; and by its upper border with the anterior and posterior 
ethmoidal vessels, the nasal and supra-trochlear nerve. 

The Rectus Externus (abductor), the longest of the straight muscles, 
arises by two distinct heads, one from the common tendon, the other with 

muscle. 5. The superior oblique muscle. 6. Its cartilaginous pulley. 7. Its reflected 
tendon. 8. The inferior oblique muscle ; the small square knob at its commencement 
is a piece of its bony origin broken off. 9. The superior rectus. 10. The internal rectus 
almost concealed by the optic nerve. 11. Part of the external rectus, showing its two 
heads of origin. 12. The extremity of the external rectus at its insertion ; the inter- 
mediate portion of the muscle having been removed. 13. The inferior rectus. 14. 
The tunica albuginea, formed by the expansion of the tendons of the four recti. 

M 



178 OBLIQUUS INFERIOR. 

the origin of the superior rectus from the margin of the optic foramen ; 
the nasal, third and sixth nerves passing between its heads. It is inserted 
into the outer surface of the globe of the eye at a little more than two lines 
from the margin of the cornea. 

Relations. — By its internal surface with the third, the nasal, the sixth, 
and the optic nerve, the ciliary ganglion and nerves, the ophthalmic artery 
and vein, the adipose tissue of the orbit, the inferior oblique muscle and 
the eyeball. By its external surface with the periosteum of the orbit ; and 
by the upper border with the lachrymal vessels and nerve and the lachry- 
mal gland. 

The recti muscles present several characters which are common to all ; 
thus they are thin, have each the form of an isosceles triangle, bear the 
same relation to the globe of the eye, and are inserted in a similar manner 
into the sclerotica, at about two lines from the circumference of the cornea. 
The points of difference relate to thickness and length ; the internal rectus 
is the thickest and shortest, the external rectus the longest of the four, and 
the superior rectus the most thin. The insertion of the four recti muscles 
into the globe of the eye forms a tendinous expansion, which is continued 
as far as the margin of the cornea, and is called the tunica albuginea. 

The Obliquus Superior (trochlearis) is a fusiform muscle arising from 
the margin of the optic foramen, and from the fibrous sheath of the optic 
nerve ; it passes forwards to the pulley beneath the internal angular pro- 
cess of the frontal bone ; its tendon is then reflected beneath the superior 
rectus muscle, to the outer and posterior part of the globe of the eye, 
where it is inserted into the sclerotic coat, near the entrance of the optic 
nerve. The tendon is surrounded by a synovial membrane, while passing 
through the cartilaginous pulley. 

Relations. — By its superior surf ace with the fourth nerve, the supra- 
trochlear nerve, and with the periosteum of the orbit. By the inferior 
surface with the adipose tissue of the orbit, the upper border of the inter- 
nal rectus and the vessels and nerves in relation with that border. 

The Obliquus Inferior, a thin and narrow muscle, arises from the 
inner margin of the superior maxillary bone, immediately external to the 
lachrymal groove, and passes beneath the inferior rectus, to be inserted 
into the outer and posterior part of the eyeball, at about two lines from 
the entrance of the optic nerve. 

Relations. — By its superior surface with the inferior rectus muscle and 
with the eyeball ; and by the inferior surface with the periosteum of the 
floor of the orbit, and the external rectus muscle. 

According to Mr. Farrall* the muscles of the orbit are separated from 
the globe of the eyeball and from the structures immediately surrounding 
the optic nerve, by a distinct fascia, which is continuous with the broad 
tarsal ligament and with the tarsal cartilages. This fascia the author terms 
the tunica vaginalis oculi,\ it is pierced anteriorly for the passage of the 
six orbital muscles, by six openings through which the tendons of the 
muscles play as through pulleys. The use assigned to it by Mr. Farrall 
is to protect the eyeball from the pressure of its muscles during their ac- 
tion. By means of this structure the recti muscles are enabled to impress 

* In a paper read before the Royal Society, on the 10th of June, 1841. 
J This fascia was first described by Mr. Dalrymple in his work on the "Anatomy of 
the Human Eye." 1834. 



NASAL GROUP. 179 

a rotatory movement upon the eyeball ; and in animals provided with a 
retractor muscle, they also act as antagonists to its action. 

Actions. — The levator palpebrae raises the upper eyelid. The four recti, 
acting singly, pull the eyeball in the four directions ; upwards, downwards, 
inwards, and outwards. Acting by pairs, they carry the eyeball in the 
diagonal of these directions, viz. upwards and inwards, upwards and out- 
wards, downwards and inwards, or downwards and outwards. Acting all 
together, they directly retract the globe within the orbit. The superior 
oblique muscle, acting alone, rolls the globe inwards and forwards, and 
carries the pupil outwards and downwards to the lower and outer angle 
of the orbit. The inferior oblique, acting alone, rolls the globe outwards 
and backwards, and carries the pupil outwards and upwards to the upper 
and outer angle of the eye. Both muscles acting together, draw the eye- 
ball forwards, and give the pupil that slight degree of eversion which en- 
ables it to admit the largest field of vision. 

4. Nasal Group. — Pyramidalis nasi, 
Compressor nasi, 
Dilatator naris. * 

The Pyramidalis Nasi is a small pyramidal slip of muscular fibres sent 
downwards upon the bridge of the nose by the occipito-frontalis. It is 
inserted into the tendinous expansion of the compressores nasi. 

Relations. — By its upper surface with the integument ; by its under sur- 
face w T ith the periosteum of the frontal and nasal bone. Its outer border 
corresponds with the edge of the orbicularis palpebrarum, and its inner 
border with its fellow, from which it is separated by a slight interval. 

The Compressor Nasi is a thin and triangular muscle ; it arises by its 
apex from the canine fossa of the superior maxillary bone, and spreads out 
upon the side of the nose into a thin tendinous expansion, wmch is con- 
tinuous across its ridge with the muscle of the opposite side. 

Relations. — By its superficial surface with the levator labii superioris 
proprius, the levator labii superioris alaeque nasi, and the integument ; by 
its deep surface with the superior maxillary and nasal bone, and with the 
alar and lateral cartilages of the nose. 

The Dilatator Naris is a thin and indistinct muscular apparatus ex- 
panded upon the ala of the nostril, and consisting of an anterior and a 
posterior slip. The anterior slip (levator proprius alae nasi anterior) ex- 
tends between the lateral and alar cartilage at about midway between the 
tip and the attached margin of the nose. The posterior slip (levator pro- 
prius alae nasi posterior) is attached above to the margin of the nasal pro- 
cess of the superior maxillary bone, and below to the small cartilages of 
the ala nasi. These muscles are difficult of dissection from the close 
adherence of the integument to the nasal cartilages. 

Actions. — The pyramidalis nasi, as a point of attachment of the occi- 
pito-frontalis, assists that muscle in its action : it also draws down the 
inner angle of the eyebrow, and by its insertion fixes the aponeurosis of 
the compressores nasi. The compressores nasi appear to act in expanding 
rather than in compressing the nares ; hence probably the compressed 
state of the nares from paralysis of these muscles in the last moments of 
life, or in compression of the brain. The use of the dilatator naris is ex- 
pressed in its name. 



130 SUPERIOR LABIAL GROUP. 

5. Superior Labial Group. — Orbicularis oris, 

Levator labii superioris alaeque nasi, 

Levator labii superioris proprius, 

Levator anguli oris, 

Zygomaticus major, 

Zygomaticus minor, 

Depressor labii superioris alaeque nasi. 

The Orbicularis Oris is a sphincter muscle, completely surrounding 
the mouth, and possessing consequently neither origin nor insertion. It 
is composed of two thick semicircular planes of fibres, which embrace the 
rima of the mouth, and interlace at their extremities, where they are con- 
tinuous with the fibres of the buccinator, and of the other muscles con- 
nected with the angle of the mouth. The upper segment is attached by 
means of a small muscular fasciculus (naso-labialis) to the columna of the 
nose ; and other fasciculi connected with both segments and attached to 
the maxillary bones are termed " accessorii." 

Relations. — By its superficial surface with the integument of the lips, 
with which it is closely connected. By its deep surface with the mucous 
membrane of the mouth, the labial glands and coronary arteries being 
interposed. By its circumference with the numerous muscles which move 
the lips, and by the inner border with the mucous membrane of the rima 
of the mouth. 

The Levator Labii Superioris Aljeque Nasi is a thin triangular 
muscle : it anses from the upper part of the nasal process of the superior 
maxillary bone ; and becoming broader as it descends, is inserted by two 
distinct portions into the ala of the nose and upper lip. 

Relations. — By its superficial surface with part of the orbicularis palpe- 
brarum muscle, the facial artery, and the integument. By its deep surface 
with the superior maxillary bone, compressor nasi, alar cartilage, and 
w r ith a muscular fasciculus attached only to the bone, and thence called 
musculus anomalus. 

The Levator Labii Superioris Proprius is a thin quadrilateral mus- 
cle : it arises from the lower border of the orbit, and passing obliquely 
downwards and inwards, is inserted into the integument of the upper lip ; 
its deep fibres being blended with those of the orbicularis. 

Relations. — By its superficial surface with the lower segment of the 
.orbicularis palpebrarum, with the facial artery, and with the integument. 
By its deep surface with the origins of the compressor nasi and levator 
anguli oris muscle, and with the infra-orbital artery and nerve. 

The Levator Anguli Oris arises from the canine fossa of the superior 
maxillary bone, and passes outwards to be inserted into the angle of the 
mouth, intermingling its fibres with those of the orbicularis, zygomatici, 
and depressor anguli oris. 

Relations. — By its superficial surface with the levator labii superioris 
proprius, the branches of the infra-orbital artery and nerve, and inferiority 
with the integument. By its deep surface with the superior maxillary bone 
and buccinator muscle. 

The Zygomatic muscles are two slender fasciculi of fibres which arise 
from the malar bone, and are inserted into the angle of the mouth, where 
they are continuous with the other muscles attached to this part. The 
zygomaticus minor is situated in front of the major, and is continuous at 



INFERIOR LABIAL GROUP. 181 

its insertion with the levator labii superioris proprius ; it is not unfre- 
quently wanting. 

Relations. — The zygomatkus major muscle is in relation by its superficial 
surface with the lower segment of the orbicularis palpebrarum above, and 
the fat of the cheek and integument for the rest of its extent. By its deep 
surface with the malar bone, the masseter, and buccinator muscle, and 
the facial vessels. The zygomaticus minor, being in front of the major, 
has no relation with the masseter muscle, while inferiorly it rests upon the 
levator anguli oris. 

The Depressor Labii Superioris Aljeque Nasi (myrtiformis) is seen 
by drawing upwards the upper lip, and raising the mucous membrane. 
It is a small oval slip of muscle, situated on each side of the fraenum, 
arising from the incisive fossa, and passing upwards to be inserted into 
the upper lip and into the ala and columna of the nose. This muscle is 
continuous by its outer border with the edge of the compressor nasi. 

Relations. — By its superficial surface with the mucous membrane of the 
mouth, the orbicularis oris and levator labii superioris alseque nasi muscle; 
and by its deep surface with the superior maxillary bone. 

Actions. — The orbicularis oris produces the direct closure of the lips 
by means of its continuity at the angles of the mouth with the fibres of the 
buccinator. When acting singly in the forcible closure of the mouth, the 
integument is thrown into wrinkles in consequence of its firm connexion 
with the surface of the muscle. The levator labii superioris alseque nasi 
lifts the upper lip with the ala of the nose, and expands the opening of the 
nares. The depressor labii superioris alseque nasi is the antagonist to this 
muscle, drawing the upper lip and ala of the nose downwards, and con- 
tracting the opening of the nares. The levator labii superioris proprius 
is the proper elevator of the upper lip ; acting singly it draws the lip a 
little to one side. The levator anguli oris lifts the angle of the mouth and 
draws it inwards, while the zygomatic pull it upwards and outwards, as 
in laughing. 

6. Inferior Labial Group. — Depressor labii inferioris, 

Depressor anguli oris, 
Levator labii inferioris. 

Dissection. — To dissect the inferior labial region continue the vertical 
section from the margin of the lower lip to the point of the chin. Then 
carry an incision along the margin of the lower jaw to its angle. Dissect 
off the integument and superficial fascia from the w T hole of this surface, 
and the muscles of the inferior labial region will be exposed. 

The Depressor Labii Inferioris (quadratus menti) arises from the 
oblique line by the side of the symphysis of the lower jaw, and passing 
upwards and inwards is inserted into the orbicularis muscle and integu- 
ment of the lower lip. 

Relation's. — By its superficial surface with the platysma myoides, part 
of the depressor anguli oris, and with the integument of the chin, with 
which it is closely connected. By the deep surface with the levator labii 
inferioris, the labial glands and mucous membrane of the lower lip, and 
with the mental nerve and artery. 

The Depressor Anguli Oris (triangularis oris) is a triangular plane of 
muscle arising by a broad base from the external oblique ridge of the 



182 MAXILLARY GROUP. 

lower jaw, and inserted by its apex into the angle of the mouth, where it 
is continuous with the levator anguli oris and zygomaticus major. 

Relations. — By its superficial surface with the integument ; and by its 
deep surface with the depressor labii inferioris, the buccinator, and the 
branches of the mental nerve and artery. 

The Levator Labii Inferioris (levator menti) is a small conical slip 
of muscle arising from the incisive fossa of the lower jaw, and inserted 
into the integument of the chin. It is in relation with the mucous mem- 
brane of the mouth, with its fellow, and with the depressor labii inferioris. 

Jictions. — p The depressor labii inferioris draws the lower lip directly 
downwards, and at the same time a little outwards. The depressor an- 
guli oris, from the radiate direction of its fibres, will pull the angle of the 
mouth either downwards and inwards, or downwards and outwards, and 
be expressive of grief; or acting with the levator anguli oris and zygo- 
maticus major, it will draw the angle of the mouth directly backwards. 
The levator labii inferioris raises and protrudes the integument of the 
chin. « 

7. Maxillary group. — Masseter, 

Temporalis, 
Buccinator, 
Pterygoideus externus, 
Pterygoideus internus. 

Dissection. — The masseter has been already exposed by the preceding 
dissection. 

The Masseter (fxafrcrao/xai, to chew,) is a short, thick, and sometimes 
quadrilateral muscle, composed of two planes of fibres, superficial and 
deep. The superficial layer arises by a strong aponeurosis from the 
tuberosity of the superior maxillary bone, the lower border of the malar 
bone and zygoma, and passes backwards to be inserted into the ramus 
and angle of the inferior maxilla. The deep layer arises from the poste- 
rior part of the zygoma, and passes forwards, to be inserted into the 
upper half of the ramus. This muscle is tendinous and muscular in its 
structure. 

Relations. — By its external surface with the zygomaticus major and 
risorius Santorini muscle, the parotid gland and Stenon's duct, the trans- 
verse facial artery, the pes anserinus and the integument. By its internal 
surface with the temporal muscle, the buccinator, from which it is separated 
by a mass of fat, and with the ramus of the lower jaw. By its posterior 
border with the parotid gland ; and by the anterior border with the facial 
artery and vein. 

Dissection. — Make an incision along the upper border of the zygoma, 
for the purpose of separating the temporal fascia from its attachment. Then 
saw through the zygomatic process of the malar bone, and through the 
root of the zygoma, near to the meatus auditorius. Draw down the 
zygoma, and with it the origin of the masseter, and dissect the latter 
muscle away from the ramus and angle of the inferior maxilla. Now re- 
move the temporal fascia from the rest of its attachment, and the whole of 
the temporal muscle will be exposed. 

The Temporal is a broad and radiating muscle occupying a considera- 
ble extent of the side of the head and filling the temporal fossa. It is 
covered in by a very dense fascia (temporal fascia) which is attached along 



BUCCINATOR — PTERYGOIDEI. 183 

the temporal ridge on the side of the skull, extending from the external 
angular process of the frontal bone to the mastoid portion of the temporal ; 
interiorly, it is connected to the upper border of the zygoma. The muscle 
arises by tendinous fibres from the whole length of the temporal ridge, 
and by muscular fibres from the temporal fascia and entire surface of the 
temporal fossa. Its fibres converge to a strong and narrow tendon, which 
is inserted into the apex of the coronoid process, and for some way down 
upon its inner surface. 

Relations. — By its external surface with the temporal fascia, which se- 
parates it from the attollens and attrahens aurem muscle, the temporal 
vessels and nerves ; and with the zygoma and masseter. By its internal 
surface with the bones forming the temporal fossa, the external pterygoid 
muscle, a part of the buccinator, and the internal maxillary artery with its 
deep temporal branches. 

By sawing through the coronoid process near to its base, and pulling it 
upwards, together with the temporal muscle, which may be dissected from 
the fossa, we obtain a view of the entire extent of the buccinator and of 
the external pterygoid muscle. 

The Buccinator (buccina, a trumpet), the trumpeter's muscle, arises 
from the alveolar process of the superior maxillary and from the external 
oblique line of the inferior maxillary bone, as far forward as the second 
bicuspid tooth, and from the pterygo-maxillary ligament. This ligament 
is the raphe of union between the buccinator and superior constrictor 
muscle, and is attached by one extremity to the hamular process of the 
internal pterygoid plate, and by the other to the extremity of the molar 
ridge. The fibres of the muscle converge towards the angle of the mouth 
where they cross each other, the superior being continuous with the infe- 
rior segment of the orbicularis oris, and the inferior with the superior 
segment. The muscle is invested externally by a thin fascia. 

Relations. — By its external surface, posteriorly with a large and rounded 
mass of fat, which separates the muscle from the ramus of the low T er jaw, 
the temporal, and the masseter ; anteriorly with the risorius Santorini, the 
zygomatici, the levator anguli oris, and the depressor anguli oris. It is 
also in relation with a part of Stenon's duct, which pierces it opposite the 
second molar tooth of the upper jaw, with the transverse facial artery, the 
branches of the facial and buccal nerve, and the facial artery and vein. 
By its internal surface with the buccal glands and mucous membrane of 
the mouth. 

The External Pterygoid is a short and thick muscle, broader at its 
origin than at its insertion. It arises by two heads, one from the pterygoid 
ridge on the greater ala of the sphenoid ; the other from the external 
pterygoid plate and tuberosity of the palate bone. The fibres pass back- 
wards, to be inserted into the neck of the lower jaw and the interarticular 
fibro-cartilage. The internal maxillary artery frequently passes between 
the two heads of this muscle. 

Relations. — By its external surface, with the ramus of the lower jaw, 
the temporal muscle, and the internal maxillary artery ; by its internal 
surface, with the internal pterygoid muscle, internal lateral ligament of the 
lower jaw, arteria meningea media, and inferior maxillary nerve ; and by 
its upper border, with the muscular branches of the inferior maxillary 
nerve ; the internal maxillary artery passes between the two heads of this 
muscle, and its lower origin is pierced by the buccal nerve. 



184 AURICULAR GROUP. 

The external pterygoid muscle must now be removed, the ramus of the 
lower jaw sawn through its lower third, and the head of the bone dislo- 
cated from its socket and withdrawn, for the purpose of seeing the ptery- 
goideus internus. 

The Internal Pterygoid is a thick quadrangular muscle. It arises 
from the pterygoid fossa, and descends obliquely backwards, to be in- 
serted into the" ramus and angle of the lower jaw : it resembles the masse- 
ter in appearance and direction, and was named by Winslow the internal 
masseter. 

Relations. — By its external surface, with the external pterygoid, the in- 
ferior maxillary nerve and its branches, the internal maxillary artery and 
branches, the internal lateral ligament, and the ramus of the lower jaw. 
By its internal surface, with the tensor palati, superior constrictor and 
fascia of the pharynx ; and by its posterior border, with the parotid gland. 

Actions. — The maxillary muscles are the 
Fig. 108* active agents in mastication, and form an ap- 

paratus beautifully fitted for that office. The 
buccinator circumscribes the cavity of the 
mouth, and with the aid of the tongue, keeps 
the food under the immediate pressure of the 
teeth. By means of its connexion with the 
superior constrictor, it shortens the cavity of 
the pharynx from before backwards, and be- 
comes an important auxiliary in deglutition. 
The temporal, the masseter, and the internal 
pterygoid, are the bruising muscles, drawing 
the lower jaw against the upper with great 
force. The two latter, by the obliquity of their direction, assist the ex- 
ternal pterygoid in grinding the food, by carrying the lower jaw forward 
upon the upper ; the jaw being brought back again by the deep portion 
of the masseter and posterior fibres of the temporal. The whole of these 
muscles, acting in succession, produce a rotatory movement of the teeth 
upon each other, which, with the direct action of the lower jaw against 
the upper, effects the proper mastication of the food. 

8. Auricular Group. — Attollens aurem, 

Attrahens aurem, 
Retrahens aurem. 

Dissection. — The three small muscles of the ear may be exposed by 
removing a square of integument from around the auricula. This opera- 
tion must be performed with care, otherwise the muscles, which are ex 
tremely thin, will be raised with the superficial fascia. They are best 
dissected by commencing with their tendons, and thence proceeding in 
the course of their radiating fibres. 

The Attollens aurem (superior auris), the largest of the three, is a thin 
triangular plane of muscular fibres arising from the edge of the aponeurosis 
of the occipito-frontalis, and inserted into the upper part of the concha. 

It is in relation by its external surface with the integument, and by the 
internal with the temporal aponeurosis. 

* The two pterygoid muscles. The zygomatic arch and the greater part of the ramus 
of the lower jaw have been removed, in order to bring these muscles into view. 1. 
The sphenoid origin of the external pterygoid muscle. 2. Its pterygoid origin. 3. The 
internal pterygoid muscle. 




MUSCLES OF THE NECK. 185 

The Attrahens Aurem (anterior auris), also triangular, arises from 
the edge of the aponeurosis of the occipito-frontalis, and is inserted into 
the anterior part of the helix, covering in the anterior and posterior tem- 
poral arteries. 

It is in relation by its external surface with the integument ; and by the 
internal with the temporal aponeurosis and with the temporal artery and 
veins. 

The Retrahens Aurem (posterior auris), arises by three or four mus- 
cular *slips from the mastoid process. They are inserted into the posterior 
surface of the concha. 

It is in relation by its external surface with the integument, and by its 
internal surface with the mastoid portion of the temporal bone. 

Actions. — The muscles of the auricular region possess but little action 
in man ; they are the analogues of important muscles in brutes. Their 
use is sufficiently explained in their names. 

MUSCLES OF THE NECK. 

The muscles of the neck may be arranged into eight groups correspond- 
ing with the natural divisions of the region ; they are the — 

1. Superficial group. 

2. Depressors of the os hyoides and larynx. 

3. Elevators of the os hyoides and larynx. 

4. Lingual group. 

5. Pharyngeal group. 

6. Soft palate group. 

7. Prevertebral group. 

8. Proper muscles of the larynx. 

And each of these groups consist of the following muscles : — viz. 

1. Superficial Group. Stylo-glossus, 
Platysma-myoides, Palato-glossus. 
Stemo-cleido-mastoideus. 

5. Muscles of the Pharynx. 

2. Depressors of the os hyoides Constrictor inferior, 

and larynx. Constrictor medius, 

Sterno-hyoideus, Constrictor superior, 

Sterno-thyroideus, Stylo-pharyngeus, 

Thyro-hyoideus, Palato-pharyngeus. 
Omo-hyoideus. 

6. Muscles of the soft Palate. 

3. Elevators of tlie os hyoides Levator palati, 

and larynx. Tensor palati, 

Digastricus, Azygos uvulae, 

Stylo-hyoideus, Palato-glossus, 

Mylo-hyoideus, Palato-pharyngeus. 
Genio-hyoideus, 

Genio-hyo-glossus. 7. Prcevertebral Group. 

Rectus anticus major, 

4. Muscles of the Tongue. Rectus anticus minor, 

Genio-hyo-glossus, Scalenus anticus, 

Hyo-glossus, Scalenus posticus, 

Lingualis, Longus colli. 
16* 



186 



PLATYSMA MYOIDES. 



8. Muscles of the Larynx. 
Crico-thyroideus, 
Crico-arytsenoideus, posticus, 



Crico-arytaenoideus, lateralis, 

Thyro-arytaenoideus. 

Arytaenoideus. 



Dissection. — The dissection of the neck should be commenced by 
making an incision along the middle line of its fore part from the chin to 
the sternum, and bounding it superiorly and inferiorfy by two transverse 
incisions ; the superior one being carried along the margin of the lower 
jaw, and across the mastoid process to the tubercle on the occipital bone, 
the inferior one along the clavicle to the acromion process. The square 
flap of integument thus included should be turned back from the entire 
side of the neck, which brings into view the superficial fascia, and on the 
removal of a thin layer of superficial fascia the platysma myoides will be 
exposed. 

The Platysma Myoides (?rXa<n)s, fxvg stSog y broad muscle-like lamella), 
is a thin plane of muscular fibres, situated between the two layers of the 
superficial cervical fascia; it arises from the integument over the pectoralis 
major and deltoid muscles, and passes obliquely upwards and inwards 
along the side of the neck to be inserted into the side of the chin, oblique 
line of the lower jaw, the angle of the mouth, and into the cellular tissue 
of the face. The most anterior fibres are continuous beneath the chin, 
with the muscle of the opposite side ; the next interlace with the depressor 
anguli oris, and depressor labii inferioris, and the most posterior fibres are 
disposed in a transverse direction across the side of the face, arising in the 
cellular tissue covering the parotid gland, and inserted into the angle of 
the mouth, constituting the risorius Santorini. The entire muscle is ana- 
logous to the cutaneous muscle of brutes, the panniculus carnosus. 

Relations. — By its external 
surface with the integument, 
with which it is closely adhe- 
rent below, but loosely above. 
By its internal surface, below 
the clavicle, with the pectoralis 
major and deltoid ; in the neck, 
with the external jugular vein 
and deep cervical fascia ; on 
the face, with the parotid 
gland, the masseter, the facial 
artery and vein, the buccinator, 
the depressor anguli oris, and 
the depressor labii inferioris. 

On raising the platysma 
throughout its whole extent, 
the sterno-mastoid is brought 
into view. 

The Sterno-cleido-mastoid 
is the large oblique muscle of 

♦The muscles of the anterior aspect of the neck; on the left side the superficial mus- 
cles are seen, and on the right the deep. 1. The posterior belly of the digastricus mus- 
cle. 2. Its anterior belly. The aponeurotic pulley, through which its tendon is seen 
passing, is attached to the body of the os hyoides. 3, 4. The stylo-hyoideus muscle, 
transfixed by the posterior belly of the digastricus. 5. The mylo-hyoideus. G. The 



Fig. 109* 




DEPRESSORS OF THE OS HYOIDES AND LARYNX. 187 

the neck, and is situated between two layers of the deep cervical fascia. 
It arises, as implied in its name, from the sternum and clavicle (xXsiiSiov), 
and passes obliquely upwards and backwards to be inserted into the mas- 
toid process and into the superior curved line of the occipital bone. The 
sternal portion arises by a rounded tendon, increases in breadth as it 
ascends, and spreads out to a considerable extent at its insertion. The 
clavicular portion is broad and fleshy, and separate from the sternal portion 
below, but becomes gradually blended with its posterior surface as it 
ascends. 

Relations. — By its superficial surface with the integument, the platysma 
myoides, the external jugular vein, superficial branches of the anterior 
cervical plexus of nerves, and the anterior layer of the deep cervical fascia. 
By its deep surface with the deep layer of the cervical fascia ; with the 
sterno-clavicular articulation, the sterno-hyoid, sterno-thyroid, omo-hyoid, 
sc'uleni, levator anguli scapulae, splenii, and the posterior belly of the di- 
gastric muscle ; with the phrenic nerve, and the posterior, and supra-sca- 
pular artery ; with the deep lymphatic glands, the sheath of the common 
carotid and internal jugular vein, the descendens noni nerve, the external 
carotid artery and its posterior branches, the commencement of the internal 
carotid artery ; with the cervical plexus of nerves, the pneumogastric, the 
spinal accessory, the hypoglossal, the sympathetic and the facial nerve, 
and with the parotid gland. It is pierced on this aspect by the spinal ac- 
cessory nerve and by the branches of the mastoid artery. The anterior 
border of the muscle is the posterior boundary of the great anterior triangle, 
the other two boundaries being the middle line of the neck in front, and 
the lower border of the jaw above. It is the guide to the operations for 
the ligature of the common carotid artery and arteria innominata, and for 
cesophagotomy. The posterior border is the anterior boundary of the great 
posterior triangle ; the other two boundaries being the anterior border of 
the trapezius behind, and the clavicle below. 

Actions. — The platysma produces a muscular traction on the integu- 
ment of the neck, which prevents it from falling so flaccid in old persons 
as would be the case if the extension of the skin were the mere result of 
elasticity. It draws also upon the angle of the mouth, and is one of the 
depressors of the lower jaw. The transverse fibres draw the angle of the 
mouth outwards and slightly upwards. The sterno-mastoid muscles are 
the great anterior muscles of connexion between the thorax and the head. 
Both muscles acting together bow the head directly forwards. The cla- 
vicular portions, acting more forcibly than the sternal, give stability and 
steadiness to the head in supporting great weights. Either muscle acting 
singly would draw the head towards the shoulder of the same side, and 
carry the face towards the opposite side. 

Second Group. — Depressors of the Os Hyoides and Larynx. 
Sterno-hyoid, Thyro-hyoid, 

Sterno-thyroid, Omo-hyoid. 

geniohyoideus. 7. The tongue. 8. The hyo-glossus. 9. The styloglossus. 10. The 
stylo-pharyngeus. 11. The sterno-mastoid muscle. 12. Its sternal origin. 13. Its cla- 
vicular origin. 14. The sterno-hyoid. 15. The sterno-thyroid of the right side. 16. 
The thyro-hyoid. 17. The hyoid portion of the omo-hyoid. 18, 18. Its scapular portion ; 
on the left side, the tendon of the muscle is seen to be bound down by a portion of the 
deep cervical fascia. 19. The clavicular portion of the trapezius. 20. The scalenus 
amicus of the right side. 21. The scalenus posticus. 



188 DEPRESSORS OF THE OS HYOIDES AND LARYNX. 

Dissection. — These muscles are brought into view by removing the 
deep fascia from off the front of the neck between the two sterno-mastoid 
muscles. The omo-hyoid to be seen in its whole extent requires that the 
sterno-mastoid muscle should be divided from its origin and turned aside. 
The Sterno-hyoideus is a narrow riband-like muscle, arising from the 
posterior surface of the first bone of the sternum and inner extremity of 
the clavicle. It is inserted into the lower border and posterior surface of 
the body of the os hyoides. The sterno-hyoidei are separated by a con- 
siderable interval at the root of the neck,' but approach each other as they 
ascend : they are frequently traversed by a tendinous intersection. 

Relations. — By its external surface with the deep cervical fascia, the 
platysma myoides and sterno-mastoid muscle ; by its internal surface with 
the sterno-thyroid, and thyro-hyoid muscle, and the superior thyroid 
artery. 

The Sterno-thyroideus, broader than the preceding beneath which it 
lies, arises from the posterior surface of the upper bone of the sternum, 
and from the cartilage of the first rib ; it is inserted into the oblique line 
on the great ala of the thyroid cartilage. The inner borders of these 
muscles lie in contact along the middle line, and they are generally marked 
by a tendinous intersection at their lower part. 

Relations. — By its external surface with the stemo-hyoid, omo-hyoid, 
and sterno-mastoid muscle ; by its internal surface, with the trachea and 
inferior thyroid veins, with the thyroid gland, the lower part of the larynx, 
the sheath of the common carotid artery and internal jugular vein, with 
the subclavian vein and vena innominata, and on the right side with the 
arteria innominata. The middle thyroid vein lies along its inner border. 
The Thyro-hyoideus is the continuation upwards of the sterno-thyroid 
muscle. It arises from the oblique line on the thyroid cartilage, and is 
inserted into the lower border of the body and great cornu of the os 
hyoides. 

Relations. — By its external surface with the sterno-hyoid and omo-hyoid 
muscle ; by its internal surface with the great ala of the thyroid cartilage, 
the thyro-hyoidean membrane, and the superior laryngeal artery and 
nerve. 

The Omo-hyoideus (wjxor, shoulder) is a double-bellied muscle passing 
obliquely across the neck from the scapula to the os hyoides : it forms an 
obtuse angle behind the sterno-mastoid muscle, and is retained in that 
position by means of a process of the deep cervical fascia which is con- 
nected to the inner border of its tendon. It arises from the upper border 
of the scapula, and from the transverse ligament of the supra-scapular 
notch, and is inserted into the lower border of the body of the os hyoides. 
Relations. — By its superficial surface with the trapezius, the subclavius 
and clavicle, the deep cervical fascia and platysma myoides, the sterno- 
mastoid, and the integument. By its deep surface with the brachial plexus, 
the scaleni muscles, the phrenic nerve, the sheath of the common carotid 
artery and jugular vein, the descendens noni nerve, the sterno-thyroid, 
and thyro-hyoid muscle, and the sterno-hyoid at its insertion. The sca- 
pular portion of the muscle divides the great posterior triangle into a su- 
perior or occipital triangle ; and an inferior or subclavian triangle, which 
contains the subclavian artery and brachial plexus of nerves ; the other 
two boundaries of the latter being the sterno-mastoid in Iront and the cla- 
vicle below. The hyoid portion of the muscle divides the great anterior 



ELEVATORS OF THE OS HYOIDES. 189 

triangle into an inferior carotid triangle situated below the muscle, and 
into a superior triangle which lies above the muscle and is again subdi- 
vided by the digastricus into the submaxillary triangle and the superior 
carotid triangle. The other two boundaries of the inferior carotid triangle, 
are the middle line of the neck in front and the anterior border of the 
sterno-mastoid behind. The other boundaries of the superior carotid tri- 
angle are the posterior belly of the digastricus muscle above and the an- 
terior border of the sterno-mastoid behind. 

Actions. — The four muscles of this group are the depressors of the os 
hyoides and larynx. The three former drawing these parts downwards 
in the middle line, and the two omo-hyoidei regulating their traction to 
the one or other side of the neck, according to the position of the head. 
The omo-hyoid muscles by means of their connexion with the cervical 
fascia are rendered tensors of that portion of the deep cervical fascia which 
covers in the lower part of the neck, between the two sterno-mastoid 
muscles. 

Third Group. — Elevators of the Os Hyoides. 

Digastricus, Genio-hyoid, 

Stylo-hyoid, Genio-hyo-glossus. 

Mylo-hyoid, 

Dissection. — These are best dissected by placing a high block beneath 
the neck, and throwing the head backwards. The integument has been 
already dissected away, and the removal of the cellular tissue and fat 
brings them clearly into view. 

The Digastricus (<5/g, twice, yaov^, belly) is a small muscle situated 
immediately beneath the side of the body of the lower jaw ; it is fleshy at 
each extremity, and tendinous in the middle. It arises from the digastric 
fossa, upon the inner side of the mastoid process of the temporal bone, 
and is inserted into a depression on the inner side of the lower jaw, close 
to the symphysis. The middle tendon is held in connexion with the body 
of the os hyoides by an aponeurotic loop, through which it plays as through 
a pulley; the loop being lubricated by a synovial membrane. A thin 
layer of aponeurosis is given off from the tendon of the digastricus at each 
side, which is connected with the body of the os hyoides, and forms a 
strong plane of fascia between the anterior portions of the two muscles. 
This fascia is called the supra-hyoidean. 

Relations. — By its superficial surface with the platysma myoides, the 
sterno-mastoid, the anterior fasciculus of the stylo-hyoid muscle, the 
parotid gland, and submaxillary gland. By its deep surface with the 
styloid muscles, the hyo-glossus, the mylo-hyoid muscle, the external 
carotid artery, the lingual and the facial arteries, the internal carotid artery, 
the jugular vein, and the hypoglossal nerve. The digastric muscle forms 
the two inferior boundaries of the submaxillary triangle, the superior boun- 
dary being the side of the body of the lower jaw. In the posterior half 
of the submaxillary triangle are situated the submaxillary gland and the 
facial artery. 

The Stylo-hyoideus is a small and slender muscle situated in imme- 
diate relation with the posterior belly of the digastricus muscle, being 
pierced by its tendon. It arises from the middle of the styloid process, 
and is inserted into the body of the os hyoides near the middle line. 



190 MYLO-HYOIDEUS GENIO-HYOIDEUS. 

Relations. — By its superficial surface with the posterior belly of the 
digastricus, the parotid gland and submaxillary gland ; its deep relations 
are similar to those of the posterior belly of the digastricus. 

The digastricus and stylo-hyoideus must be removed from their con- 
nexion with the lower jaw and os hyoides, and turned aside in order to 
see the next muscle. 

The Mylo-hyoideus (puXvi, mola, i. e. attached to the molar ridge of 
the lower jaw) is a broad triangular plane of muscular fibres, forming, 
with its fellow of the opposite side, the inferior wall or floor of the mouth. 
It arises from the molar ridge on the lower jaw, and proceeds obliquely 
inwards to be inserted into the raphe of the two muscles and into the 
body of the os hyoides ; the raphe is sometimes deficient at its anterior 
part. 

Relations. — By its superficial, or inferior surface,' with the platysma 
myoides, the digastricus, the supra-hyoidean fascia, the submaxillary gland 
and the submental artery. By its deep or superior surface, with the genio- 
hyoideus, the genio-hyo-glossus, the stylo-glossus, the gustatory nerve, the 
hypoglossal nerve, Wharton's duct, the sublingual gland, and the mucous 
membrane of the floor of the mouth. 

After the mylo-hyoideus has been examined, it should be cut away from 
its origin and insertion, and completely removed. The view of the next 
muscles would also be greatly improved by dividing the lower jaw on the 
near side of the symphysis, and drawing it outwards, or by removing it 
altogether, if the ramus have been already cut across in dissecting the in- 
ternal pterygoid muscle. The tongue may then be drawn out of the mouth 
by means of a hook. b 

The Genio-hyoideus (ysvsov, the chin) arises from a small tubercle upon 
the inner side of the symphysis of the lower jaw, and is inserted into the 
upper part of the body of the os hyoides. It is a short and slender muscle, 
very closely connected with the border of the following. 

Relations. — By its superficial or inferior surface, with the mylo-hyoideus , 
by the deep or superior surface, with the lower border of the genio-hyo- 
glossus. 

The Genio-hyo-glossus (yXuada, the tongue) is a triangular muscle, 
narrow and pointed at its origin from the lower jaw, broad and fan-shaped 
at its attachment to the tongue. It arises from a tubercle immediately 
above that of the genio-hyoideus, and spreads out to be inserted into the 
whole length of the tongue, from its base to the apex, and into the body 
of the os hyoides. 

Relations. — By its inner surface with its fellow of the opposite side. 
By its outer surface with the mylo-hyoideus, the hyo-glossus, the stylo- 
glossus, lingualis, the sublingual gland, the lingual artery, and the hypo- 
glossal nerve. By its upper border with the mucous membrane of the floor 
of the mouth, in the situation of the fraenum linguae ; and by the lower 
border with the genio-hyoideus. 

Actions. — The whole of this group of muscles acts upon the os hyoides 
when the lower jaw is closed, and upon the lower jaw when the os hyoides 
is drawn downwards, and fixed by the depressors of the os hyoides and 
larynx. The genio-hyo-glossus is, moreover, a muscle of the tongue ; its 
action upon that organ shall be considered with the next group. 



MUSCLES OF THE TONGUE. 



191 



Fig. 110.* 



Fourth Group. — Muscles of the Tongue. 

Genio-hyo-glossus, Styloglossus, 

Hyo-glossus, Palatoglossus. 

Lingualis, 

These are already exposed by the preparation we have just made ; there 
remains, therefore, only to dissect and examine them. 

The Genio-hyo-glossus, the first of these muscles, has been described 
with the last group. 

The Hyo-glossus is a square-shaped plane of muscle, arising from the 
whole length of the great cornu and from the body of the os hyoides, and 
inserted between the stylo-glossus and lingualis into the side of the tongue. 
The direction of the fibres of that portion of the muscle wnicj|arises from 
the body is obliquely backwards ; and that from the great cojjpi obliquely 
forwards; hence they are described by Albinus as two distinct Muscles, 
under the names of the basio-glossus, and cerato-glossus, to which he 
added a third fasciculus, arising from the lesser cornu, and spreading 
along the side of the tongue, the chondro-glossus. The basio-glossus 
slightly overlaps the cerato-glossus at its upper part, and is separated from 
it by the transverse portion of the stylo-glossus. 

Relations. — By its external surface 
with the digastric muscle, the stylo- 
hyoideus, stylo-glossus, and mylo- 
hyoideus, with the gustatory nerve, the 
hypoglossal nerve, Wharton's duct and 
the sublingual gland. By its internal 
surface with the middle constrictor of 
the pharynx, the lingualis, the genio- 
hyo-glossus, the lingual artery, and 
the glosso-pharyngeal nerve. 

The Lingualis. — The fibres of this 
muscle may be seen towards the apex 
of the tongue, issuing from the interval 
between the hyo-glossus and genio- 
hyo-glossus ; it is best examined by 
removing the preceding muscle. It 
consists of a small fasciculus of fibres, 
running longitudinally from the base, 
where it is attached to the os hyoides, 
to the apex of the tongue. It is in re- 
lation by its under surface with the ranine artery. 

* The styloid muscles and the muscles of the tongue. 1. A portion of the temporal 
bone of the left side of the skull, including the styloid and mastoid processes, and the 
meatus auditoiius externus. 2, 2. The right side of the lower jaw, divided at its sym- 
physis; the left side having been removed. 3. The tongue. 4. The genio-byoideus 
muscle. 5. The genio-hyo-glossus. 6. The hyo-glossus muscle, its basio-glossus portion. 
7. Its cerato-glossus portion. 8. The anterior fibres of the lingualis issuing from between 
the hyo-glossus and genio-hyo-glossus. 9. The stylo-glossus muscle, with a small portion 
of the stylo-maxillary ligament. 10. The stylo-hyoid. 11. The stylo-pharyngeus muscle. 
12. The os hyoides. 13. The thyro-hyoidean membrane. 14. The thyroid cartilage. 

15. The thyro-hyoideus muscle arising from the oblique line on the thyroid cartilage. 

16. The cricoid cartilage^ 17. The crico-thyroidean membrane, through which the ope- 
ration of laryngotorny is performed. 18. The trachea. 19. The commencement of the 
awophagus. 




192 MUSCLES OF THE PHARYNX. 

The Styloglossus arises from the apex of the styloid process, and 
from the stylo-maxillary ligament ; it divides upon the side of the tongue 
into two portions, one transverse, which passes transversely inwards be- 
tween the two portions of the hyo-glossus, and is lost among the transverse 
fibres of the substance of the tongue, and another longitudinal, which 
spreads out upon the side of the tongue as far as its tip. 

Relations. — By its external surface with the internal pterygoid muscle, 
the gustatory nerve, the parotid gland, sublingual gland, and the mucous 
membrane of the floor of the tongue. By its internal surface with the 
tonsil, the superior constrictor muscle of the pharynx, and the hyo-glossus 
muscle. 

The Palato-glossus passes between the soft palate, and the side of the 
base of the tongue, forming a projection of the mucous membrane, which 
is called the anterion pillar of the soft palate. Its fibres are lost superiorly 
among the muscular fibres of the palato-pharyngeus, and inferiorly among 
the fibres of the stylo-glossus upon the side of the tongue. This muscle 
with its fellow constitutes the constrictor isthmi faucium. 

Actions. — The genio-hyo-glossus muscle effects several movements of 
the tongue, as might be expected from its extent. When the tongue is 
steadied and pointed by the other muscles, the posterior fibres of the genio- 
hyo-glossus would dart it from the mouth, while its anterior fibres would 
restore it to its original position. The whole length of the muscle acting 
upon the tongue, would render it concave along the middle line, and form 
a channel for the current of fluid towards the pharynx, as in sucking. The 
apex of the tongue is directed to the roof of the mouth, and rendered con- 
vex from before backwards by the linguales. The hyo-glossi, by drawing 
down the sides of the tongue, render it convex along the middle line. It 
is drawn upwards at its base by the palato-glossi, and backwards or to 
either side by the stylo-glossi. Thus the whole of the complicated move- 
ments of the tongue may be explained, by reasoning upon the direction 
of the fibres of the muscles, and their probable actions. The palato-glossi 
muscles, assisted by the uvula, have the power of closing the fauces com- 
pletely, an action which takes place in deglutition. 

Fifth Group. — Muscles of the Pharynx. 

Constrictor inferior, 
Constrictor medius, 
Constrictor superior, 
Stylo-pharyngeus, 
Palato-pharyngeus. 

Dissection. — To dissect the pharynx, the trachea and oesophagus are to 
be cut through at the lower part of the neck, and drawn upw T ards by di- 
viding the loose cellular tissue which connects the pharynx to the vertebral 
column. The saw is then to be applied behind the styloid processes, and 
the base of the skull sawn through. The vessels and loose structure should 
be removed from the preparation, and the pharynx stuffed with tow or 
wool for the purpose of distending it, and rendering the muscle more easy 
of dissection. The pharynx is invested by a proper pharyngeal fascia. 

The Constrictor Inferior, the thickest of the three muscles of this 
class, arises from the upper rings of the trachea, the cricoid cartilage, and 
the oblique line of the thyroid. Its fibres spread out and are inserted into 



CONSTRICTOR SUPERIOR — STYLO-PHARYNGEUS. 193 

the fibrous raphe of the middle of the pharynx, the inferior fibres being 
almost horizontal, and the superior oblique, and overlapping the middle 
constrictor. 

Relations.^— By its external surface with the anterior surface of the ver- 
tebral column, the longus colli, the sheath of the common carotid artery, 
the sterno-thyroid muscle, the thyroid gland, and some lymphatic glands. 
By its internal surface with the middle constrictor, the stylo-pharyngeus, 
the palato-pharyngeus, and the mucous membrane of the pharynx. By its 
lower border, near the cricoid cartilage, it is in relation with the recurrent 
nerve ; and by the upper border with the superior laryngeal nerve. The 
fibres of origin of this muscle are blended with those of the sterno-hyoid, 
sterno-thyroid, and crico-thyroid, and it frequently forms a tendinous arch 
across the latter. 

This muscle must be removed before the next can be examined. 

The Constrictor Medius arises from the great cornu of the os hyoides, 
from the lesser cornu, and from the stylo-hyoidean ligament. It radiates 
from its origin upon the side of the pharynx, the lower fibres descending 
and being overlapped by the constrictor inferior, and the upper fibres 
ascending so as to cover in the constrictor superior. It is inserted into the 
raphe and by a fibrous aponeurosis into the basilar process of the occipital 
bone. 

Relations. — By its external surface with the vertebral column, the longus 
colli, rectus anticus major, the carotid vessels, inferior constrictor, hyo- 
glossus muscle, lingual artery, pharyngeal plexus of nerves, and some 
lymphatic glands. By its internal surface, with the superior constrictor, 
stylo-pharyngeus, palato-pharyngeus, and mucous membrane of the pha- 
rynx. 

The upper portion of this muscle must be turned down, to- bring the 
whole of the superior constrictor into view ; in so doing, the stylo-pharyn- 
geus muscle will be seen passing beneath its upper border. 

The Constrictor Superior is a thin and quadrilateral plane of muscu- 
lar fibres arising from the extremity of the molar ridge of the lower jaw, 
from the pterygo-maxillary ligament, and from the lower half of the inter- 
nal pterygoid plate, and inserted into the raphe and basilar process of the 
occipital bone. Its superior fibres are arched and leave an interval be- 
tween its upper border and the basilar process, which is deficient in mus- 
cular fibres, and it is overlapped inferiorly by the middle constrictor. 
Between the side of the pharynx and the ramus of the lower jaw is a 
triangular interval, the maxillo-pharyngeal space, which is bounded on the 
inner side by the superior Constrictor muscle ; on the outer side by the 
internal pterygoid muscle ; and behind by the rectus anticus major and 
vertebral column. In this space are situated the internal carotid artery, 
the internal jugular vein, and the glossopharyngeal, pneumogastric, spinal 
accessory, and hypo-glossal nerve. 

Relations. — By its external surface with the vertebral column and its 
muscles, behind ; with the vessels and nerves contained in the maxillo- 
pharyngeal space laterally, the middle constrictor, stylo-pharyngeus, and 
tensor palati muscle. By its internal surface with the levator palati, 
palato-pharyngeus, tonsil, and*-mucous membrane of the pharynx, the 
pharyngeal fascia being interposed. 

The STYLo-PHARYNGEuSfcis^Tlong and slender muscle arising from the 
inner side of the base orthe styloid process ; it descends between the 
17 n 



194 



MUSCLES OF THE SOFT PALATE. 



Fig. Ill * 




superior and middle constrictor muscles, and 
spreads out beneath the mucous membrane 
of the pharynx, its inferior fibres being in- 
serted into the posterior border of the thyroid 
cartilage. 

Relations. — By its external surface with 
the stylo-glossus muscle, external carotid 
artery, parotid gland, and the middle con- 
strictor. By its internal surface with the 
internal carotid artery, internal jugular vein, 
superior constrictor, palato-pharyngeus, and 
mucous membrane. Along its lower border 
is seen the glosso-pharyngeal nerve which 
crosses it, opposite the root of the tongue, to 
pass between the superior and middle con- 
strictor and behind the hyo-glossus.. 

The palato-pharyngeus is described with 
the muscles of the soft palate. It arises from 
the soft palate, and is inserted into the inner surface of the pharynx, and 
posterior border of the thyroid cartilage. 

Actions. — The three constrictor muscles are important agents in deglu- 
tition ; they contract upon the morsel of food as soon as it is received by 
the pharynx, and convey it downwards into the oesophagus. The stylo- 
pharyngei draw the pharynx upwards and widen it laterally. The palato- 
pharyngei also draw it upwards, and with the aid of the uvula close the 
opening of the fauces. 

Sixth Group. — Muscles of the Soft Palate. 

Levator palati, 
Tensor palati, 
Azygos uvulae, 
Palato-glossus, 
Palato-pharyngeus. 

Dissection. — To examine these muscles, the pharynx must be opened 
from behind, and the mucous membrane carefully removed from off the 
posterior surface of the soft palate. 

The Levator Palati, a moderately thick muscle, arises from the ex- 
tremity of the petrous bone and from the posterior and inferior aspect of 
the Eustachian tube, and passing down by the side of the posterior nares 
spreads out in the structure of the soft palate as far as the middle line. 

Relations. — Externally with the tensor palati and superior constrictor 
muscle ; internally and posteriorly with the mucous membrane of the 
pharynx and soft palate ; and by its lower border with the palato-pha- 
ryngeus. 

* A side view of the muscles of the pharynx. 1. The trachea. 2. The cricoid car- 
tilage. 3. The crico-thyroid membrane. 4. The thyroid cartilage. 5. The thyro-hyoi- 
dean membrane. 6. The os hyoides. 7. The stylo-hyoidean ligament. 8. The oeso- 
phagus. 9. The inferior constrictor. 10. The middle constrictor. 11. The superior 
constrictor. 12. The stylo-pharyngeus muscle passing down between the superior and 
middle constrictor. 13. The upper concave border of the superior constrictor; at this 
point the muscular fibres of the pharynx are deficient. «14. The ptery^o-maxillary liga- 
ment. 15. The buccinator muscle. 1G. The orbicularis oris. 17. The mylo-hyoideus. 




PALATO-GLOSSUS — PALATO-PHARYNGEUS. 195 

This muscle must be turned down from ri g . 112* 

its origin on one side, and removed, and the 
superior constrictor dissected away from its 
pterygoid origin, to bring the next muscle 
into view. 

The Tensor Palati (circumflexus) is a 
slender and flattened muscle ; it arises from 
the scaphoid fossa at the base of the inter- 
nal pterygoid plate and from the anterior 
aspect of the Eustachian tube. It descends 
to the hamular process, around which it 
turns and expands into a tendinous aponeu- 
rosis, which is inserted into the transverse 
ridge on the horizontal portion of the palate bone, and into the raphe. 

Relations. — By its external surface with the internal pterygoid muscle ; 
by its internal surface with the levator palati, internal pterygoid plate, 
and superior constrictor. In the soft palate, its tendinous expansion is 
placed in front of the other muscles and in contact with the mucous mem- 
brane. 

The Azygos UVuLiE is not a single muscle, as might be inferred from 
its name, but a pair of small muscles placed side by side in the middle 
line of the soft palate. They arise from the spine of the palate bone, and 
are inserted into the uvula. By their anterior surface they are connected 
with the tendinous expansion of the levatores palati, and by the posterior 
with the mucous membrane. 

The two next muscles are brought into view throughout the whole of 
their extent, by raising the mucous membrane from off the pillars of the 
soft palate at each side. 

The Palato-glossus (constrictor isthmi faucium) is a small fasciculus 
of fibres that arises in the soft palate, and descends to be inserted into the 
side of the tongue. It is the projection of this small muscle, covered by 
mucous membrane, that forms the anterior pillar of the soft palate. It has 
been named constrictor isthmi faucium from a function it performs in 
common with the palato-pharyngeus, viz. of constricting the opening of 
the fauces. 

The Palato-pharyngeus forms the posterior pillar of the fauces ; it 
arises by an expanded fasciculus from the lower part of the soft palate, 
where its fibres are continuous with those of the muscle of the opposite 

* The muscles of the soft palate. 1. A transverse section through the middle of the 
base of the skull, dividing the basilar process of the occipital bone in the middle line, 
and the petrous portion of the temporal bone at each side. 2. The vomer covered by- 
mucous membrane and separating the two posterior nares. 3, 3. The Eustachian tubes. 
4. The levator palati muscle of the left side; the right has been removed. 5. The ha- 
mular process of the internal pterygoid plate of the left side, around which the aponeu- 
rosis of the tensor palati is seen turning. 6. The pterygo-maxillary ligament. 7. The 
superior constrictor muscle of the left side, turned aside. 8. The azygos uvulae muscle. 
9. The internal pterygoid plate. 10. The external pterygoid plate. 1 1. The tensor pa- 
lati muscle. 12. Its aponeurosis expanding in the structure of the soft palate. 13. The 
external pterygoid muscle. 14. The attachments of two pairs of muscles cut short; the 
superior pair belong to the genio-hyo-glossi muscles ; the inferior pair to the genio- 
hyoidei. 15. The attachment of the rnylo-hyoideus of one side and part of the opposite. 
16. The anterior attachments of the digastric muscles. 17. The depression on the lower 
jaw corresponding with the submaxillary gland. The depression above the mylo-hyoi- 
deus, on which the number 15 rests, corresponds with the situation of the sublingual 
gland. 



196 PREVERTEBRAL MUSCLES. 

side ; and is inserted into the posterior border of the thyroid cartilage. 
This muscle is broad above where it forms the whole thickness of the 
lower half of the soft palate, narrow in the posterior pillar, and again broad 
and thin in the pharynx where it spreads out previously to its insertion. 

Relations. — In the soft palate it is in relation with the mucous membrane 
both by its anterior and posterior surface ; above, with the muscular layer 
formed by the levator palati, and below with the mucous glands situated 
along the margin of the arch of the palate. In the posterior pillar of the 
palate, it is surrounded for two-thirds of its extent by mucous membrane. 
In the pharynx, it is in relation by its outer surface with the superior and 
middle constrictor muscles, and by its inner surface with the mucous 
membrane of the pharynx, the pharyngeal fascia being interposed. 

Actions. — The azygos uvulae shortens the uvula. The levator palati 
raises the soft palate, while the tensor spreads it out laterally so as to form 
a septum between the pharynx and posterior nares. Taking its fixed point 
from below, the tensor palati will dilate the Eustachian tube. The palato- 
glossus and pharyngeus constrict the opening of the fauces, and by draw- 
ing down the soft palate they serve to press the mass of food from the 
dorsum of the tongue into the pharynxl 

Seventh Group.- — Prevertebral Muscles. 

Rectus anticus major, 
Rectus anticus minor, 
Scalenus anticus, 
Scalenus posticus, 
Longus colli. 

Dissection. — These muscles have already been exposed by the removal 
of the face from the anterior aspect of the vertebral column ; all that is 
further needed is the removal of the fascia by which they are invested. 

The Rectus Anticus Major, broad and thick above, and narrow and 
pointed below, arises from the anterior tubercles of the transverse processes 
of the third, fourth, fifth, and sixth cervical vertebrae, and is inserted into 
the basilar process of the occipital bone. 

Relations. — By its anterior surface with the pharynx, the internal carotid 
artery, internal jugular vein, superior cervical ganglion, sympathetic nerve, 
pneumogastric, and spinal accessory nerve. By its posterior surface with 
the longus colli, rectus anticus minor, and superior cervical vertebrae. 

The Rectus Anticus Minor arises from the anterior border of the la- 
teral mass of the atlas, and is inserted into the basilar process ; its fibres 
being directed obliquely upwards and inwards. 

Relations. — By its anterior surface with the rectus anticus major, and 
externally with the superior cervical ganglion of the sympathetic. By its 
-posterior surface with the articulation of the condyle of the occipital bone 
with the atlas, and with the anterior occipito-atloid ligament. 

The Scalenus Anticus is a triangular muscle, as its name implies, 
situated at the root of the neck and appearing like a continuation of the 
rectus anticus major; it arises from the anterior tubercles of the transverse 
processes of the third, fourth, fifth, and sixth cervical vertebrae, and is in- 
serted into the tubercle upon the inner border of the first rib. 

Relations. — By its anterior surface with the sterno-mastoid and omo- 
hyoid muscle, with the cervicalis superficialis and posterior scapular artery, 



SCALENUS POSTICUS — LONGUS COLLI. 



197 



Fig. 113.f 



with the phrenic nerve, and with the subclavian vein, by which it is se- 
parated from the subclavius muscle and clavicle. By its posterior surface 
with the nerves which go to form the brachial plexus, and below with the 
subclavian artery. By its inner side it is separated from the longus colli 
by the vertebral artery. Its relations with the subclavian artery and vein 
are very important, the vein being before and the artery behind the 
muscle/ 

The Scalenus Posticus arises from the 
posterior tubercles of all the cervical ver- 
tebrae excepting the first. It is inserted by 
two fleshy fasciculi into the first and second 
ribs. The anterior (scalenus medius) of the 
two fasciculi is large, and occupies all the 
surface of the first rib between the groove 
for the subclavian artery and the tuberosity. 
The posterior (scalenus posticus) is small, 
and is attached to the second rib. Albinus 
and Soemmering make five scaleni. 

Relations. — By its anterior surface with 
the brachial plexus and subclavian artery ; 
posteriorly with the levator anguli scapula?, 
cervicalis ascendens, transversalis colli, and 
sacro-lumbalis ; internally with the first in- 
tercostal muscle, the first rib, the inter- 
transverse muscles, and cervical vertebrae ; 
and externally with the sterno-mastoid, omo- 
hyoid, supra-scapular and posterior scapu- 
lar arteries. 

The Longus Colli is a long and flat muscle, consisting of two portions. 
The upper arises from the anterior tubercle of the atlas, and is inserted 
into the transverse processes of the third, fourth, and fifth cervical verte- 
brae. The lower portion arises from the bodies of the second and third, 
and transverse processes of the fourth and fifth, and passes down the neck, 
to be inserted into the bodies of the three lower cervical and three upper 
dorsal vertebrae. We should thus arrange these attachments in a tabular 
form : — 




Upper 
portion. 

Lower 
portion. 



Origin. Insertion. 

Atlas " ~ ■ ) 3d, 4th, and 5th transverse processes. 

2d and 3d bodies C 3 lower cervical vertebrae, bodies. 
4th and 5th trans- < 
verse processes. ( 3 upper dorsal, bodies. 



In general terms, the muscle is attached to the bodies and transverse 

* In a subject dissected in the school of the Middlesex hospital during the winter of 
1841 by Mr. Joseph Rogers, the subclavian artery of the left side was placed with the 
vein in front of the scalenus anticus muscle. 

-j- The prevertebral group of muscles of the neck. 1. The rectus anticus major mu.s- 
cle. 2. The scalenus anticus. 3. The lower part of the longus colli of the right side; 
it is concealed superiorly by the rectus anticus major. 4. The rectus anticus minor. 5. 
The upper portion of the longus colli muscle. 6. Its lower portion ; the figure rests 
upon the seventh cervical vertebra. 7. The scalenus posticus. 8. The rectus lateralis of 
the left side. 9. .One of the intertransversales muscles. 

17* 



198 



MUSCLES OF THE BACK. 



processes of the five superior cervical vertebrae above, and to the bodies 
of the last three cervical and first three dorsal below. 

Relations. — By its anterior surface, with the pharynx, oesophagus, the 
sheath of the common carotid, internal jugular vein and pneumogastric 
nerve, the sympathetic nerve, inferior laryngeal nerve, and inferior thyroid 
artery. By its posterior surface it rests upon the cervical and upper dor- 
sal vertebrae. 

.Actions. — The rectus anticus major and minor preserve the equilibrium 
of the head upon the atlas ; and, acting conjointly with the longus colli, 
flex and rotate the head and the cervical portion of the vertebral column. 
The scaleni muscles, taking their fixed point from below, are flexors of 
the vertebral column ; and, from above, elevators of the ribs, and there- 
fore inspiratory muscles. 

Eighth Group. — Muscles of the Larynx. 

These muscles are described with the anatomy of the larynx, in Chap- 
ter XI. 

MUSCLES OF THE TRUNK. 



The muscles of the trunk may be subdivided into four natural groups ; 



viz. 



1. Muscles of the back. 

2. Muscles of the thorax. 



3. Muscles of the abdomen. 

4. Muscles of the perineum. 



1. Muscles of the Back. — The region of the back, in consequence of its 
extent, is common to the neck, the upper extremities, and the abdomen. 
The muscles of which it is composed are numerous, and maybe arranged 
into six layers. 



First Layer. 

Trapezius, 
Latissimus dorsi. 

Second Layer. 

Levator anguli scapulae, 
Rhomboideus minor, 
Rhomboideus major. 

Third Layer. 

Serratus posticus superior, 
Serratus posticus inferior, 
Splenius capitis, 
Splenius colli. 

Fourth Layer. 

(Dorsal Group.) 
Sacro-lumbalis, 
Longissimus dorsi, 
Spinalis dorsi. 



(Cervical Group.) 
Cervicalis ascendens, 
Transversalis colli, 
Trachelo-mastoideus, 
Complexus. 

Fifth Layer. 

(Dorsal Group.) 
Semi-spinalis dorsi, 
Semi-spinalis colli. 

(Cervical Group.) 
Rectus posticus major, 
Rectus posticus minor, 
Rectus lateralis, 
Obliquus inferior, 
Obliquus superior. 

Sixth Layer. 
Multifidus spinas, 
Levatores costarum, 
Supra-spinales, 
Inter-spinales, 
Inter-transversales. 



MUSCLES OF THE BACK. 199 

First Layer. 

Dissection. — The muscles of this layer are to be dissected by making 
an incision along the middle line of the back, from the tubercle on the 
occipital bone to the coccyx. From the upper point of this incision carry 
a second along the side of the neck, to the middle of the clavicle. Infe- 
riorly, an incision must be made from the extremity of the sacrum, along 
the crest of the ileum, to about its middle. For the convenience of dis- 
section, a fourth may be carried from the middle of the spine to the acro- 
mion process. The integument and superficial fascia, together, are to be 
dissected off the muscles, in the course of their fibres, over the whole of 
this region. 

The Trapezius muscle (trapezium, a quadrangle with unequal sides) 
arises from the superior curved line of the occipital bone, from the liga- 
mentum nuchas, supra-spinous ligament, and spinous processes of the last 
cervical and all the dorsal vertebrae. The fibres converge from these 
various points, and are inserted into the scapular third of the clavicle, the 
acromion process, and the whole length of the upper border of the spine 
of the scapula. The inferior fibres become tendinous near the scapula, 
and glide over the triangular surface at the posterior extremity of its spine, 
upon a bursa mucosa. When the trapezius is dissected on both sides, 
the two muscles resemble a trapezium, or diamond-shaped quadrangle, on 
the posterior part of the shoulders : hence the muscle was formerly named 
cucullaris (cucullus, a monk's cowl). The cervical and upper part of the 
dorsal portion of the muscle is tendinous at its origin, and forms, with the 
muscle of the opposite side, a kind of tendinous ellipse. 

Relations. — By its superficial surface, with the integument and super- 
ficial fascia, to which it is closely adherent by its cervical portion, loosely 
by its dorsal portion. By its deep surface, from above downwards, with 
the complexus, splenius, levator anguli scapulae, supra-spinatus, a small 
portion of the serratus posticus superior, rhomboideus minor, rhomboideus 
major, intervertebral aponeurosis which separates it from the erector 
spinse, and with the latissimus dorsi. The anterior border of the cervical 
portion of this muscle forms the posterior boundary of the posterior tri- 
angle of the neck. The clavicular insertion of the muscle sometimes ad- 
vances to the middle of the clavicle, or as far as the outer border of the 
sterno-mastoid, and occasionally it has been seen to overlap the latter. 
This is a point of much importance to be borne in mind in the operation 
for ligature of the subclavian artery. The spinal accessory nerve passes 
beneath the anterior border, near to the clavicle, previously to its distribu- 
tion to the muscle. 

The ligamentum nuchas is a thin cellulo-fibrous layer extended from the 
tubercle and spine of the occipital bone, to the spinous process of the 
seventh cervical vertebra, where it is continuous with the supra-spinous 
ligament. It is connected with the spinous processes of the rest of the 
cervical verteorae, with the exception of the atlas, by means of a small 
fibrous slip which is sent off by each. It is the analogue of an important 
elastic ligament in animals. 

The Latissimus Dorsi muscle covers the whole of the lower part of the 
back and loins. It arises from the spinous processes of the seven inferior 
dorsal vertebrae, from all the lumbar and sacral spinous processes, from the 
posterior third of the crest of the ilium, and from the three lower ribs ; the 



200 



MUSCLES OF THE BACK. 



latter origin takes place by muscular slips, which indigitate with the ex- 
ternal oblique muscle of the abdomen. The fibres from this extensive 



Fig. 1 14.* 




origin converge as they ascend, and cross the inferior angle of the scapula; 
they then curve around the lower border of the teres major muscle, and 
terminate in a short quadrilateral tendon, f which lies in front of the tendon 
of the teres, and is inserted into the bicipital groove. A synovial bursa is 
interposed between the muscle and the lower angle of the scapula, and 

* The first and second and part of the third layer of muscles of the back; the first 
layer being shown upon the right, and the second on the left side. 1. The trapezius 
muscle. 2. The tendinous portion which, with a corresponding portion in the opposite 
muscle, forms the tendinous ellipse on the back of the neck. 3. The acromion process 
and spine of the scapula. 4. The latissimus dorsi muscle. 5. The deltoid. 0. The 
muscles of the dorsum of the scapula, infra-spinatus, teres minor, and teres major. 7. 
The external oblique muscle. 8. The gluteus medius. 9. The glutei maximi. 10. The 
levator anguli scapulae. 11. The rhomboideus minor. 12. The rhomboideus major. 
13. The splenitis capitis; the muscle immediately above, and overlaid by the splenitis, 
is the complextis. 14. The splenius colli, only partially seen; the common origin of the 
splenius is seen attached to the spinous processes below the lower border of the rhom- 
boideus major. 1 5. The vertebral aponeurosis. 16. The serratus posticus inferior. 17. 
The supra-spinatus muscle. 18. The infra-spinatus. 19. The teres minor muscle. 20. 
The teres major. 21. The long head of the triceps, passing between the teres minor 
ind major to the upper arm. 22. The serratus magnus, proceeding forwards from its 
origin at the base of the scapula. 23. The internal oblique muscle. 

•f A small muscular fasciculus from the pectoralis major is sometimes found connected 
with this tendon. 



MUSCLES OF THE BACK. 201 

another between its tendon and that of the teres major. The muscle fre- 
quently receives a small fasciculus from the scapula as it crosses its inferior 
angle. 

Relations. — By its superficial surface with the integument and superficial 
fascia ; the latter is very dense and fibrous in the lumbar region ; and with 
the trapezius. By its deep surface from below upwards, with the erector 
spinae, serratus posticus inferior, intercostal muscles and ribs, rhomboideus 
major, inferior angle of the scapula and teres major. The latissimus dorsi, 
with the teres major, forms the posterior border of the axilla. 

Second Layer. 

Dissection. — This layer is brought into view by dividing the two pre- 
ceding muscles near their insertion, and turning them to the opposite 
side. 

The Levator Anguli Scapulae arises by distinct slips, from the 
posterior tubercles of the transverse processes of the four upper cervical 
vertebrae, and is inserted into the upper angle and posterior border of 
the scapula, as far as the triangular smooth surface at the root of its 
spine. 

Relations. — By its superficial surface with the trapezius, sterno-mastoid 
and integument. By its deep surface with the splenius colli, transversalis 
colli, cervicalis ascendens, scalenus posticus, and serratus posticus supe- 
rior. The tendons of origin are interposed between the attachments of the 
scalenus posticus in front, and the splenius colli behind. 

The Rhomboideus Minor (rhombus, a parallelogram with four equal 
sides) is a narrow slip of muscle, detached from the rhomboideus major 
by a slight cellular interspace. It arises from the spinous process of the 
two last cervical vertebrae and ligamentum nuchas, and is inserted into the 
edge of the triangular surface, on the posterior border of the scapula. 

The Rhomboideus Major arises from the spinous processes of the last 
cervical and four upper dorsal vertebrae and from the inter- spinous liga- 
ments ; it is inserted into the posterior border of the scapula as far as its 
inferior angle. The upper and middle portion of the insertion is effected 
by means of a tendinous band which is attached in a longitudinal direction 
to the posterior border of the scapula. 

Relations. — By their superficial surface the two rhomboid muscles are 
in relation with the trapezius, and the rhomboideus major with the latis- 
simus dorsi and integument. By their deep surface they cover in the ser- 
ratus posticus superior, part of the erector spinae, the intercostal muscles 
and ribs. 

Third Layer. 

Dissection. — The third layer consists of muscles which arise from the 
spinous processes of the vertebral column, and pass outwards. It is brought 
into view by dividing the levator anguli scapulae near its insertion, and 
reflecting the two rhomboid muscles upwards from their insertion into the 
scapula. The latter muscles should now be removed. 

The Serratus Posticus Superior is situated at the upper part of the 
thorax ; it arises by the ligamentum nuchae, from the spinous processes of 
the three last cervical and those of the two upper dorsal vertebrae. The 
muscle passes obliquely downwards, and outwards, and is inserted by four 



202 MUSCLES OF THE BACK. 

serrations into the upper border of the second, third, fourth, and fifth 

Relations.— By its superficial surface with the trapezius, rhomboideus 
major and minor, and serratus magnns. By its deep surface with the 
splenitis, the upper part of the erector spina?, the intercostal muscles and 
ribs. . 

The Serratus Posticus Inferior arises from the processes and mter- 
spinous ligaments of the two last dorsal and three upper lumbar vertebra?, 
and passing obliquely upwards is inserted by four serrations into the lower 
border of the four lower ribs. Both muscles are constituted by a thin 
aponeurosis for about half their extent. 

Relations. — By its superficial surface with the latissimus dorsi, its tendi- 
nous origin being inseparably connected with the aponeurosis of that muscle. 
By its deep surface with the aponeurosis of the obliquus internus, with 
which it is also closely adherent ; with the erector spina?, the intercostal 
muscles and lower ribs. The upper border is continuous with a thin ten- 
dinous layer, the vertebral aponeurosis. The Vertebral aponeurosis is a 
thin membranous expansion composed of longitudinal and transverse 
fibres, and extending the whole length of the thoracic region. It is at- 
tached mesially to the spinous processes of the dorsal vertebra?, and exter- 
nally to the angles of the ribs ; superiorly it is continued upwards beneath 
the serratus posticus superior, with the lower border of which it is some- 
times connected. It serves to bind down the erector spina?, and separate 
it from the superficial muscles. 

The serratus posticus superior must be removed from its origin and 
turned outwards, to bring into view the whole extent of the splenius 
muscle. 

The Splenius Muscle is single at its origin, but divides soon after into 
two portions, which are destined to distinct insertions. It arises by the 
lower half of the ligamentum nucha?, from the spinous processes of the 
five last cervical, and from the spinous processes and interspinous liga- 
ments of the six upper dorsal vertebrae ; it divides as it ascends the neck 
into the splenius capitis and colli. The splenius capitis is inserted, into 
the rough surface of the occipital bone between the two curved lines, and 
into the mastoid portion of the temporal bone. 

The splenius colli is inserted into the posterior tubercles of the trans- 
verse processes of the three or four upper cervical vertebra?. 

Relations. — By its superficial surface with the trapezius, sterno-mastoid, 
levator anguli scapula?, rhomboideus minor and major, and serratus pos- 
ticus superior. By its deep surface with the spinalis dorsi, longissimus dorsi, 
semi-spinalis colli, complexus, trachelo-mastoid, and transversalis colli. 
The tendons of insertion of the splenius colli are interposed between the 
insertions of the levator anguli scapulae in front, and the transversalis colli 
behind. 

The splenii of opposite sides of the neck leave between them a trian- 
gular interval, in which the complexus is seen. 

Fourth Layer. 

Dissection. — The two serrati and two splenii muscles must be removed 
by cutting them away from their origins and insertions, to bring the fourth 
layer into view. 

Three of these muscles, viz. sacro-lumbalis, longissimus dorsi, and 



MUSCLES OF THE BACK. 



203 



Fig. 115* 



spinalis dorsi, are associated under the name of erector spina?. They 
occupy the lumbar and dorsal portion of the back. The remaining four 
are situated in the cervical region. 

The Sacro-lumbalis and Longissimus Dorsi arise by a common origin 
from the posterior third of the crest of the ilium, from the posterior surface 
of the sacrum, and from the lumbar vertebra? ; opposite the last rib a line 
of separation begins to be perceptible between the two muscles. The 
sacro-lumbalis is inserted by separate tendons into the angles of the six 
lower ribs. On turning the muscle a little out- 
wards, a number of tendinous slips will be seen 
taking their origin from the ribs, and terminating 
in a muscular fasciculus, by which the sacro- 
lumbalis is prolonged to the upper part of the 
thorax. This is the musculus accessorius ad 
sacro-lumbalem : it arises from the angles of the 
six lower ribs, and is inserted by separate ten- 
dons into the angles of the six upper ribs. 

The longissimus dorsi is inserted into all the 
ribs, between their tubercles and angles. 

The Spinalis Dorsi arises from the spinous 
processes of the two upper lumbar and three 
lower dorsal vertebra?, and is inserted into the 
spinous processes of all the upper dorsal verte- 
brae ; the two muscles form an ellipse, which, 
appears to enclose the spinous processes of all 
the dorsal vertebra?. 

Relations. — The erector spina? muscle is in 
relation by its superficial surface (in the lumbar 
region) with the conjoined aponeurosis of the 
transversalis and internal oblique muscle, which 
separates it from the aponeurosis of the serratus 
posticus inferior, and longissimus dorsi ; (in the 
dorsal region) with the vertebral aponeurosis, 
which separates it from the latissimus dorsi, 
trapezius, and serratus posticus superior, and 
with the splenius. By its deep surface (in the 
lumbar region) with the multifidus spina?, trans- 
verse processes of the lumbar vertebra?, and with the middle layer of the 
aponeurosis of the transversalis abdominis, which separates it from the 
quadratus lumborum ; (in the dorsal region) with the multifidus spina?, 
semi-spinalis dorsi, levatores costarum, intercostal muscles, and ribs as 
far as their angles. Internally or mesially with the multifidus spina?, and 
semi-spinalis dorsi, which separate it from the spinous processes and 
arches of the vertebra?. 

The two layers of aponeurosis of the transversalis abdominis, together 

* The fourth and fifth, and part of the sixth layer of the muscles of the back. 1. The 
common origin of the erector spinse muscle. 2. The sacro-lumbalis. 3. The longissi- 
mus dorsi. 4. The spinalis dorsi. 5. The cervicalis ascendens. 6. The transversalis 
colli. 7. The trachelo-mastoideus. 8. The complexus. 9. The transversalis colli, 
showing its origin. 10. The semi-spinalis dorsi. 11. The semi-spinalis colli. 12. The 
rectus posticus minor. 13. The rectus posticus major. 14. The obliquus superior. 
If). The obliquus inferior. 16. The multifidus spina?. 17. The levatores costarum 
18. Intertransversales. 19. The quadratus lumborum. 




204 MUSCLES OF THE BACK. 

with the spinal column in the lumbar region, and the vertebral aponeu- 
rosis with the ribs and spinal column in the dorsal region, form a com- 
plete osseo-aponeurotic sheath for the erector spinae. 

The Cervicalis Ascendens is the continuation of the sacro-lumbalis 
upwards into the neck. It arises from the angles of the four upper ribs, 
and is inserted by slender tendons into the posterior tubercles of the trans- 
verse processes of the four lower cervical vertebrae. 

Relations. — By its superficial surface with the levator anguli scapulae ; 
by its deep surface with the upper intercostal muscles and ribs, and with 
the intertransverse mu cles ; externally with the scalenus posticus ; and 
internally with the transversalis colli. The tendons of insertion are inter- 
posed between the attachments of the scalenus posticus and transversalis 
colli. 

The Transversalis Colli would appear to be the continuation up- 
wards into the neck of the longissimus dorsi ; it arises from the transverse 
processes of the five upper dorsal vertebrae, and is inserted into the pos- 
terior tubercles of the transverse processes of the five middle cervical 
vertebrae. 

Relations. — By its superficial surface with the levator anguli scapula?, 
splenius and longissimus dorsi. By its deep surface with the complexus, 
trachelo-mastoideus and vertebrae ; externally with the musculus aceesso- 
rius ad sacro-lumbalem, and cervicalis ascendens ; internally with the 
trachelo-mastoideus and complexus. The tendons of insertion of this 
muscle are interposed between the tendons of insertion of the cervicalis 
ascendens on the outer side, and of origin of the trachelo-mastoid on the 
inner side. 

The Trachelo-mastoid is likewise a continuation upwards from the 
longissimus dorsi. It is a very slender and delicate muscle, arising from 
the transverse processes of the four upper dorsal and four lower cervical 
vertebrae, and inserted into the mastoid process to the inner side of the 
digastric fossa. 

Relations. — The same as those of the preceding muscle, excepting that 
it is interposed between the transversalis colli and the complexus. Its 
tendons of attachment are the most posterior of those which are connected 
with the posterior tubercles of the transverse processes of the cervical ver- 
tebrae. 

The Complexus is a large muscle, and with the splenius forms the 
great bulk of the back of the neck. It crosses the direction of the splenius, 
arising from the transverse processes of the four upper dorsal, and from 
the transverse and articular processes of the four lower cervical vertebra;, 
and is inserted into the rough surface on the occipital bone between the 
two" curved lines, near the occipital spine. A large fasciculus of the com- 
plexus is so distinct from the principal mass of the muscle as to have led 
to its description as a separate muscle under the name of biv enter cervicis. 
This appellation is not inappropriate, for the muscle consists of a central 
tendon, with two fleshy bellies. The complexus is crossed in the upper 
part of the neck by a tendinous intersection. 

Relations. — By its superficial surface with the trapezius, splenius, tra- 
chelo-mastoid, transversalis colli, and longissimus dorsi. By its deep sur- 
face with the semi-spinalis dorsi and colli, the recti and obliqui. It is 
separated from its fellow of the opposite side by the ligamentum nuchae, 
and from the semi-spinalis colli by the profunda cervicis artery and prin- 



MUSCLES OF THE BACK. 205 

ceps cervicis branch of the occipital, and by the posterior cervical plexus 
of nerves. 

Fifth Layer. 

Dissection. — The muscles of the preceding layer are to be removed by 
dividing them transversely through the middle, and turning one extremity 
upwards, the other downwards. In this way the whole of the muscles of 
the fourth layer may be got rid of, and the remaining muscles of the spine 
brought into a state to be examined. 

The Semi-spinales Muscles are connected with the transverse and 
spinous processes of the vertebrae, spanning one half of the vertebral 
column ; hence their name semi-spinales. 

The Semi-spinalis Dorsi arises from the transverse processes of the 
six lower dorsal vertebrae, and is inserted into the spinous processes of the 
four upper dorsal, and two lower cervical vertebrae. 

The Semi-spinalis Colli arises from the transverse processes of the 
four upper dorsal vertebrae, and is inserted into the spinous processes of 
the four upper cervical vertebrae, commencing with the axis. 

Relations. — By their superficial surface the semi-spinales are in relation 
from below upwards with the spinalis dorsi, longissimus dorsi, complexus, 
splenius, with the profunda cervicis and princeps cervicis artery, and pos- 
terior cervical plexus of nerves. By their deep surface with the multifidus 
spinae muscle. 

Occipital Group. — This group of small muscles is intended for the varied 
movements of the cranium on the atlas, and the atlas on the axis. They 
are extremely pretty in appearance. 

The Rectus Posticus Major arises from the spinous process of the 
axis, and is inserted into the inferior curved line of the occipital bone. 

The Rectus Posticus Minor arises from the spinous tubercle of the 
atlas, and is inserted into the rough surface on the occipital bone, beneath 
the inferior curved line. 

The Rectus Lateralis is extended between the transverse process of 
the atlas and the occipital bone ; it arises from the transverse process of 
the atlas, and is inserted into the rough surface of the occipital bone, ex- 
ternal to the condyle. 

The Obliquus Inferior arises from the spinous process of the axis, and 
passes obliquely outwards to be inserted into the extremity of the trans- 
verse process of the atlas. 

The Obliquus Superior arises from the extremity of the transverse pro- 
cess of the atlas, and passes obliquely inwards to be inserted into the rough 
surface of the occipital bone, between the curved lines. 

Relations. — By their superficial surface the recti and obliqui are in rela- 
tion with a strong aponeurosis which separates them from the complexus. 
By their deep surface with the atlas and axis, and their articulations. The 
rectus posticus major partly covers in the rectus minor. 

The rectus lateralis is in relation by its anterior surface with the internal 
jugular vein, and by its posterior surface with the vertebral artery. 

Sixth Layer. 
Dissection. — The semi-spinales muscles must both be removed to obtain 
a good view of the multifidus spinae which lies beneath them, and fills up 
the concavity between the spinous and transverse processes, the whole 
length of the vertebral column. 
18 



206 MUSCLES OF THE BACK. 

The Multifidus Spinje* consists of a great number of fleshy fasciculi 
extending between the transverse and spinous processes of the vertebrae, 
from the sacrum to the axis. Each fasciculus arises from a transverse pro- 
cess, and is inserted into the spinous process of the first or second vertebra 
above. Some deep fasciculi of the multifidus spinae have recently been 
described by Professor Theile under the name of rotatores spines. 

Relations. — By its superficial surface with the longissimus dorsi, semi- 
spinalis dorsi, and semi-spinalis colli. By its deep surface with the arches 
and spinous processes of the vertebral column, and in the cervical region 
with the ligamentum nuchEe. 

The Levatores Costarum, twelve in number on each side, arise from 
the transverse processes of the dorsal vertebrae, and pass obliquely out- 
wards and downwards to be inserted into the rough surface between the 
tubercle and angle of the rib below them. The first of these muscles 
arises from the transverse process of the last cervical vertebra, and the last 
from that of the eleventh dorsal. The levatores of the inferior ribs, besides 
the distribution here described, send a fasciculus downwards to the second 
rib below their origin, and consequently are inserted into two ribs. 

Relations. — By their superficial surface with the longissimus dorsi and 
sacro-lumbalis. By their deep surface with the intercostal muscles and 
ribs. 

The Supra -spinalis is a small and irregular muscle lying upon the 
spinous processes in the cervical region and composed of several fasciculi. 
The fasciculi arise from the inferior cervical and superior dorsal vertebrae, 
and are inserted into the spinous process of the axis. From its analogy 
to the spinalis dorsi this muscle has been named spinalis colli. It is 
sometimes wanting. 

The Interspinales are small muscular slips arranged in pairs and situ- 
ated between the spinous processes of the vertebrae. In the cervical re- 
gion there are six pairs of these muscles, the first being placed between 
the axis and third vertebra, and the sixth between the last cervical and 
first dorsal. In the dorsal region, rudiments of these muscles are occa- 
sionally met with between the upper and lower vertebrae, but are absent 
in the rest. In the lumbar region there are six pairs of interspinales, the 
first pair occupying the interspinous space between the last dorsal and 
first lumbar vertebra, and the last the space between the fifth lumbar and 
sacrum. They are thin and imperfectly developed. Rudimentary inter- 
spinales are occasionally met with between the lower part of the sacrum 
and the coccyx ; these are the analogues of the caudal muscles of brutes ; 
in man they have been named collectively the extensor coccygis. 

The Intertransversales are small quadrilateral muscles situated be- 
tween the transverse processes of the vertebrae. In the cervical region 
they are arranged in pairs corresponding with the double conformation of 
the transverse processes, the vertebral artery and anterior division of the 
cervical nerves lying between them. The rectus anticus minor and rectus 
lateralis represent the intertransversales between the atlas and cranium. 
In the dorsal region the anterior intertransversales are represented by the 
intercostal muscles, while the posterior are mere tendinous bands, mus- 
cular only between the first and last vertebrae. In the lumbar region, the 

* Professor Theile of Berlin has examined this muscle very closely, and describes a 
portion of it under the name of Rotatob.es spixje, which seems to be an unnecessary 
complication. — G. 



MUSCLES OF THE BACK. 207 

anterior intertransversales are thin, and occupy only part of the space be- 
tween the transverse processes. Analogues of posterior intertransversales 
exist in the form of small muscular fasciculi (interobliqui) extended be 
tween the rudimentary posterior transverse processes of the lumbar ver- 
tebrae. 

With regard to the origin and insertion of the muscles of the back, the 
student should be informed, that no regularity attends their attachments. 
At the best, a knowledge of their exact connexions, even were it possible 
to retain it, would be but a barren information, if not absolutely injurious, 
as tending to exclude more valuable learning. I have therefore endea- 
voured to arrange a plan, by which they may be more easily recollected, 
by placing them in a tabular form (p. 208), that the student may see, at 
a single glance, the origin and insertion of each, and compare the natural 
grouping and similarity of attachments of the various layers. In this 
manner also their actions will be better comprehended, and learnt with 
greater facility. 

Actions. — The upper fibres of the trapezius draw the shoulder upwards 
and backwards ; the middle fibres, directly backwards ; and the lower 
downwards and backwards. The lower fibres also act by producing ro- 
tation of the scapula upon the chest. If the shoulder be fixed the upper 
fibres will flex the spine towards the corresponding side. The latissimus 
dorsi is a muscle of the arm, drawing it backwards and downwards, and 
at the same time rotating it inwards ; if the arm be fixed, the latissimus 
dorsi will draw the spine to that side, and, raising the lower ribs, be an 
inspiratory muscle ; and if both arms be fixed, the two muscles will draw 
the whole trunk forwards, as in climbing or walking on crutches. The 
levator anguli scapulae lifts the upper angle of the scapula, and with it the 
entire shoulder, and the rhomboidei carry the scapula and shoulder up- 
wards and backwards. 

In examining the following table, the student will observe the constant 
recurrence of the nMUihev four in the origin and insertion of the muscles. 
Sometimes the four occurs at the top or bottom of a region of the spine, 
and frequently includes a part of two regions, and takes two from each, 
as in the case of the serrati. Again, he will perceive that the muscles of 
the upper half of the table take their origin from spinous processes, and 
pass outwards to transverse, whereas the lower half arise mostly from 
transverse processes. To the student, then, we commit these reflections, 
and leave it to the peculiar tenor of his own mind to make such arrange- 
ments as will be best retained by his memory. 

The serrati are respiratory muscles acting in opposition to each other, 
the serratus posticus superior drawing the ribs upwards, and thereby ex- 
panding the chest ; and the inferior drawing the lower ribs downwards 
and diminishing the cavity of the chest. The former is an inspiratory, 
the latter an expiratory muscle. The splenii muscles of one side draw 
the vertebral column backwards and to one side, and rotate the head to- 
wards the corresponding shoulder. The muscles of opposite sides, acting 
together, will draw the head directly backwards. They are the natural 
antagonists of the sterno-mastoid muscles. 

The sacro-lumbalis with its accessory muscle, the longissimus dorsi, and 
spinalis dorsi, are known by the general term of erectores spina, which 
sufficiently expresses their action. They keep the spine supported in the 
vertical position by their broad origin from below, and by means of their 



208 



TABLE OF ORIGIN AND INSERTION 



ORIGIN. 



Layers. 



:| 



1st Layer. 
Trapezius . . . < 

Latissimus dorsi . < 

2d Layer. 

Levator anguli sea- ) 
pulae .... J 

Rhomboideus mi- f 
nor . . . . ( 

Rhomboideus major 

3d Layer. 

Serratus posticus 
superior . . 

Serratus posticus 
inferior . . 

Splenius capitis 
Splenius colli . 

4th Layer. 

Sacro-Iumbalis . . 
Accessorius ad sa-) 
cro-lumbalem . J 

Longissimus dorsi . 

Spinalis dorsi . . < 

Cervicalis ascendens 

Transversalis colli . 

Trachelo-mastoideus 

Complexus . . . 

5th Layer. 
Semi-spinalis dorsi 

Semi-spinalis colli 

Rectus posticus ma- ~? 
jor . . . . .5 

Rectus posticus mi 
nor .... 

Rectus lateralis 
Obliquus inferior . 
Obliquus superior . 

6th Layer. 
Multifidus spinae . 

Levatores costarum 
Supra-spinales . . 

Inter-spinales . . ^ 

Inter- transversales 



Spinous Processes. 



last cervical, 

12 dorsal 
6 lower dorsal, 

5 lumbar . 



lig. nuchae and 

last cervical 

4 upper dorsal 



lig. nucha?, 
last cervical, 
2 upper dorsal 

2 lower dorsal, 
2upper lumbar 

lig. nucha?, 
last cervical, 
6 upper dorsal 



2 lower dorsal, 
2 upper lumbar 



axis 
atlas 

axis 



cervical 

Cervical and 
lumbar 



Transverse Pro- 
cesses. 



4 upper cervical 



f; 

\- 
I- 

b 



i- 



3d, 4th, 5th, 
and 6th dorsal 

4 upper dorsal, 
4 lower cervical 

4 upper dorsal, 
4 lower cervical 



6 lower dorsal 
4 upper dorsal 



atlas 

atlas 



from sacrum to 
3d cervical 

last cervical and 
eleven dorsal 



cervical and 
lumbar 



Ribs. 



• i 

3 lower 



angles of 
6 lower 



angles of 
4 upper 



Additional. 



occipital bone and> 
ligamentum nuchae 5 

sacrum and ilium . 



sacrum and ilium . 



sacrum and lumbar } 
vertebrae . 5 



OF THE MUSCLES OF THE BACK. 



209 





INSERTION. 


Spinous Processes. 


Transverse 
Processes. , 


Ribs. 


Additional. 


«... 




.... { 
. . . . { 


clavicle and spine of 

the scapula, 
posterior bicipital ridge 

of the humerus. 


. 


. • • 


. . . . { 


angle and base of the 
scapula. 


* . . . 


... 


«... 


base of the scapula. 


.... 


. 


• • 


base of the scapula. 


• 


. 


2d, 3d, 4th, and 5th. 






. . 


4 lower ribs. 




. 


4 upper cervical 


• • • • ! 


occipital and mastoid 
portion of temporal 
bone. 


i 


... . 


angles of 6 lower. 




. ... . 


. 


angles of 6 upper. 




. 


. . . { 


all the ribs between the 
tubercles and angles. 




8 upper dorsal. 


4 lower cervical. 






. 


4 lower cervical. 


- 


mastoid process. 


• 


. 


: : : : .j 


occipital bone between 
the curved lines. 


(4 upper dorsal, 
/ 2 lower cervical. 
\4 upper cervical, 
\ except atlas. 








. 


• 


. 


occipital bone. 


.... 


• • • 


. ■ . . . 


occipital bone. 


. • • . 


• • 

atlas. 


«... 


occipital bone, 
occipital bone. 


( from last lumbar to 
( axis. 

cervical. 


• • • i 


all the ribs between the 
tubercles and angles. 




cervical and lumbar. 


( cervical and 
( lumbar. 







18 



210 MUSCLES OF THE THORAX. 

insertion, by distinct tendons, into the ribs and spinous processes. Being 
made up of a number of distinct fasciculi, which alternate in their actions, 
the spine is kept erect without fatigue, even when they have to counter- 
balance a corpulent abdominal development. The continuations upwards 
of these muscles into the neck preserve the steadiness and uprightness of 
that region. When the muscles of one side act alone, the neck is rotated 
upon its axis. The complexus, by being attached to the occipital bone, 
draws the head backwards, and counteracts the muscles on the anterior 
part of the neck. It assists also in the rotation of the head. 

The semi-spinales and multifidus spines muscles act directly on the ver- 
tebrae, and contribute to the general action of supporting the vertebral 
column erect. 

The four little muscles situated between the occiput and the two first 
vertebrae, effect the various movements between these bones ; the recti 
producing the antero-posterior actions, and the obliqui the rotatory mo- 
tions of the atlas on the axis. 

The actions of the remaining muscles of the spine, the supra and inter- 
spinales and inter-transversales, are expressed in their names. They ap- 
proximate their attachments and assist the more powerful muscles in pre- 
serving the erect position of the body. 

The levatores costarum raise the posterior parts of the ribs, and are 
probably more serviceable in preserving the articulation of the ribs from 
dislocation, than in raising them in inspiration. 

MUSCLES OF THE THORAX. 

The principal muscles situated upon the thorax belong in their actions 
to the upper extremity, with which they will be described. They are the 
pectoralis major and minor, subclavius and serratus magnus. The true 
thoracic muscles are few in number, and appertain exclusively to the ac- 
tions of the ribs ; they are, the — 

Intercostales externi, 
Intercostales interni, 
Triangularis sterni. 

The intercostal muscles are two planes of muscular and tendinous 
fibres directed obliquely between the adjacent ribs and closing the inter- 
costal spaces. They are seen partially upon the removal of the pectoral 
muscles, or upon the inner surface of the chest. The triangularis sterni 
is within the chest, and requires the removal of the anterior part of the 
thorax to bring: it into view. 

The Intercostales Externi, eleven on each side, commence poste- 
riorly at the tubercles of the ribs, and advance forwards to the costal car- 
tilages, where they terminate in a thin aponeurosis, which is continued 
onwards to the sternum. Their fibres are directed obliquely downwards 
and inwards, pursuing the same line with those of the external oblique 
muscle of the abdomen. They are thicker than the internal intercostals. 

The Intercostales Interni, also eleven on each side, commence ante- 
riorly at the sternum, and extend backwards as far as the angles of the 
ribs, whence they are prolonged to the vertebral column by a thin apo- 
neurosis. Their fibres are directed obliquely downwards and backwards, 
and correspond in direction with those of the internal oblique muscle of 



MUSCLES OF THE ABDOMEN. 211 

the abdomen. The two muscles cross each other in the direction of their 
fibres. 

In structure the intercostal muscles consist of an admixture of muscular 
and tendinous fibres. They arise from the two lips of the lower border 
of the ribs, the external from the outer lip, the internal from the inner, 
and are inserted into the upper border. 

Relations. — The external intercostals, by their external surface, with the 
muscles which immediately invest the chest, viz. the pectoralis major and 
minor, the serratus magnus, serratus posticus superior and inferior, scalenus 
posticus ; sacro-lumbalis, and longissimus dorsi, with their continuations, 
the cervicalis ascendens and transversalis colli ; the levatores costarum, 
and the obliquus externus abdominis. By their internal surface with the 
internal intercostals, the intercostal vessels and nerves, and a thin aponeu- 
rosis, and posteriorly with the pleura. The internal intercostals, by their 
external surface with the external intercostals, and intercostal vessels and 
nerves ; by their internal surface with the pleura costalis, the triangularis 
sterni and diaphragm. 

Connected with the internal intercostals are a variable number of mus- 
cular fasciculi, which pass from the inner surface of one rib near its middle 
to the next or next but one below ; these are the subcostal, or more cor- 
rectly the infracostal muscles. 

The Triangularis Sterni, situated upon the inner wall of the front of 
the chest, arises by a thin aponeurosis from the side of the sternum, ensi- 
form cartilage, and sternal extremities of the costal cartilages ; and is in- 
serted by fleshy digitations into the cartilages of the third, fourth, fifth and 
sixth ribs, and often into that of the second. 

Relations. — By its external surface with the sternum, the ensiform carti- 
lage, the costal cartilages, internal intercostal muscles, and internal mam- 
mary vessels. By its internal surface with the pleura costalis, the areolar 
tissue of the anterior mediastinum and the diaphragm. The lower fibres 
of the triangularis sterni are continuous with those of the diaphragm. 

Actions.— The intercostal muscles raise the ribs when they act from 
above, and depress them when they take their fixed point from below. 
They are, therefore, both inspiratory and expiratory muscles. The trian- 
gularis sterni draws down the costal cartilages, and is, therefore, an expi- 
ratory muscle. 

MUSCLES OF THE ABDOMEN. 

The muscles of this region are, the — 

Obliquus externus (descendens), 

Obliquus internus (ascendens), 

Cremaster, 

Transversalis, 

Rectus," 

Pyramidalis, 

Quadratus lumborum, 

Psoas parvus, 

Diaphragm. 

Dissection. — The dissection of the abdominal muscles is to be commenced 
by making three incisions : — The first, vertical, in the middle line, from 
over the lower part of the sternum to the pubes ; the second oblique, from 



212 MUSCLES OF THE ABDOMEN. 

the umbilicus, upwards and outwards, to the outer side of the chest, as 
high as the fifth or sixth rib ; and the third, oblique, from the umbilicus, 
downwards and outwards, to the middle of the crest of the ilium. The 
three flaps included by these incisions should then be dissected back in 
the direction of the fibres of the external oblique muscle, beginning at the 
angle of each. The integument and superficial fascia should be dissected 
off together so as to expose the fibres of the muscle at once. 

If the external oblique muscle be dissected on both sides, a white ten- 
dinous line will be seen along the middle of the abdomen, extending from 
the ensiform cartilage to the os pubis ; this is the linea alba. A little ex- 
ternal to it, on each side, two curved lines will be observed extending 
from the sides of the chest to the os pubis, and bounding the recti muscles : 
these are the linece semilunares. Some transverse lines, linece transversa, 
three or four in number, connect the lineae semilunares with the linea 
alba. 

The External Oblique Muscle (obliquus externus abdominis descendens) 
is the external flat muscle of the abdomen. Its name is derived from the 
obliquity of its direction, and the descending course of its fibres. It 
arises by fleshy digitations from the external surface of the eight inferior 
ribs ; the five upper digitations being received between corresponding pro- 
cesses of the serratus magnus, and the three lower of the latissimus dorsi. 
Soon after its 4 origin it spreads out into a broad aponeurosis, which is in- 
serted into the outer lip of the crest of the ilium for one half its length, the 
anterior superior spinous process of the ilium, spine of the os pubis, pecti- 
neal line, front of the os pubis, and linea alba. 

The lower border of the aponeurosis, which is stretched between the 
anterior superior spinous process of the ilium and the spine of the os pubis, 
is rounded from being folded inwards, and forms Pouparfs ligament; the 
insertion into the pectineal line is GimbernaVs ligament. 

Just above the crest of the os pubis is the external abdominal ring, a 
triangular opening formed by the separation of the fibres of the aponeuro- 
sis of the external oblique. It is oblique in its direction, and corresponds 
with the course of the fibres of the aponeurosis. It is bounded below by 
the crest of the os pubis ; on either side by the borders of the aponeurosis, 
which are called pillars ; and above by some curved fibres {inter-colum- 
nar), which originate from Poupart's ligament, and cross the upper angle 
of the ring so as to give it strength. The external pillar, which is at the 
same time inferior from the obliquity of the opening, is inserted into the 
spine of the os pubis ; the internal or superior pillar forms an interlacement 
with its fellow of the opposite side over the front of the symphysis pubis. 
The external abdominal ring gives passage to the spermatic cord in the 
male and round ligament in the female : they are both invested in their 
passage through it by a thin fascia derived from the edges of the ring, and 
called inter-columnar fascia, or fascia spermatica. 

The pouch of inguinal hernia, in passing through this opening, receives 
the inter-columnar fascia, as one of its coverings. 

Relations. — By its external surface with the superficial fascia and inte- 
gument, and with the cutaneous vessels and nerves, particularly the super- 
ficial epigastric and superficial circumflexa ilii vessels. It is generally 
overlapped posteriorly by the latissimus dorsi. By its internal surface 
with the internal oblique, the lower part of the eight inferior ribs and in- 
tercostal muscles, the cremaster, the spermatic cord in the male, and the 



MUSCLES OF THE ABDOMEN. 



213 



round ligament in the female. The upper border of the external oblique 
is continuous with the pectoralis major. 

The external oblique is now to be removed by making an incision 
across the ribs, just below its origin, to its posterior border; and another 
along Poupart's ligament and the crest of the ilium. Poupart's ligament 



Fie. 110.* 




* The muscles of the anterior aspect of the trunk ; on the left side the superficial 
layer is seen, and on the right the deeper layer. 1. The pectoralis major muscle. 2. 
The deltoid ; the interval between these muscles lodges the cephalic vein. 3. The an- 
terior bordei of the latissimus dorsi. 4. The serrations of the serratus magnus. 5. The 
subclavius muscle of the right side. 6. The pectoralis minor. 7. The coracho-brachia- 
lis muscle. 8. The upper part of the biceps muscle, showing its two heads. 9. The 
coracoid process of the scapula. 10. The serratus magnus of the right side. 11. The 
external intercostal muscle of the fifth intercostal space. 12. The external oblique 
muscle. 13. Its aponeurosis; the median line to the right of this number is the linea 
alba; the flexuous line to its left is the lrnea semilunaris; and the transverse lines 
above and below the number, the linea? transversa?. 14. Poupart's ligament. 15. The 
external abdominal ring; the margin above the ring is the superior or internal pillar; 
the margin below the ring, the inferior or external pillar; the curved intercolumnar 
fibres are seen proceeding upwards from Poupart's ligament to strengthen the ring. 
The numbers 14 and 15 are situated upon the fascia lata of the thigh ; the opening im- 
mediately to the right of 15 is the saphenous opening. 16. The rectus muscle of the 
right side brought into view by the removal of the anterior segment of its sheath : * the 
posterior segment of its sheath with the divided edge of the anterior segment. 17. 
The pyramidalis muscle. 18. The internal oblique muscle. 19. The conjoined ten- 
don of the internal oblique and transversalis descending behind Poupart's ligament 
to the pectineal line. 20. The arch formed between the lower curved border of the 
interna.' oblique muscle and Poupart's ligament; it is beneath this arch that the sperm- 
atic cord and hernia pass. 



214 MUSCLES OF THE ABDOMEN. 

should be left entire, as it gives attachment to the next muscles. The 
muscle may then be turned forwards towards the linea alba, or removed 
altogether. 

The Internal Oblique Muscle (obliquus internus abdominis ascendens) 
is the middle flat muscle of the abdomen. It arises from the outer half 
of Poupart's ligament, from the middle of the crest of the ilium for two- 
thirds of its length, and by a thin aponeurosis from the spinous processes 
of the lumbar vertebrae. Its fibres diverge from their origin, so that those 
from Poupart's ligament curve downwards, those from the anterior part 
of the crest of the ilium pass transversely, and the rest ascend obliquely. 
The muscle is inserted into the pectineal line and crest of the os pubis, 
linea alba, and lower borders of the five inferior ribs. 

Along the upper three-fourths of the linea semilunaris, the aponeurosis 
of the internal oblique separates into two lamellse, which pass one in front 
and the other behind the rectus muscle to the linea alba, where they are 
inserted ; along the lower fourth, the aponeurosis passes altogether in front 
of the rectus without separation. The two layers, which thus enclose the 
rectus, form for it a partial sheath. 

The lowest fibres of the internal oblique are inserted into the pectineal 
line of the os pubis in common with those of the transversalis muscle. 
Hence the tendon of this insertion is called the conjoined tendon of the in- 
ternal oblique and transversalis. This structure corresponds' with the 
external abdominal ring, and forms a protection to what would otherwise 
be a weak point in the abdomen. Sometimes the tendon is insufficient to 
resist the pressure from Within, and becomes forced through the external 
ring ; it then forms the distinctive covering of direct inguinal hernia. 

The spermatic cord passes beneath the arched border of the internal 
oblique muscle, between it and Poupart's ligament. During its passage 
some fibres are given off from the lower border of the muscle, which ac- 
company the cord downwards to the testicle, and form loops around it : 
this is the cremaster muscle. In the descent of oblique inguinal hernia, 
which travels the same course with the spermatic cord, the cremaster 
muscle forms one of its coverings. 

The Cremaster, considered as a distinct muscle, arises from the mid- 
dle of Poupart's ligament, and forms a series of loops upon the spermatic 
cord. A few of its fibres are inserted into the tunica vaginalis, the rest 
ascend along the inner side of the cord, to be inserted, with the conjoined 
tendon, into the pectineal line of the os pubis. 

Relations. — The internal oblique is in relation, by its external surface, 
with the external oblique, latissimus dorsi, spermatic cord, and external 
abdominal ring. By its internal surface, with the transversalis muscle, 
the fascia transversalis, the internal abdominal ring, and spermatic cord. 
By its lower and arched border, with the spermatic cord, forming the 
upper boundary of the spermatic canal. 

The cremaster is in relation, by its external surface, with the aponeuro- 
sis of the external oblique and intercolumnar fascia ; and by its internal 
surface, with the fascia propria of the spermatic cord. 

The internal oblique muscle is to be removed by separating it from its 
attachments to the ribs above, and to the crest of the ilium and Poupart's 
ligament below. It should be divided behind by a vertical incision, ex- 
tending from the last rib to the crest of the ilium, as its lumbar attachment 
cannot at present be examined. The muscle is then to be turned for- 



TRANSVERSALIS. 



215 



Fig. 117. 



wards. Some degree of care will be required in performing this dissec- 
tion, from the difficulty of distinguishing between this muscle and the one 
beneath. A thin layer of cellular tissue is all that separates them for the 
greater part of their extent. Near the crest of the ilium, the circumflexa 
ilii artery ascends between the two muscles, and forms a valuable guide 
to their separation. Just above Poupart's ligament they are so closely 
connected, that it is impossible to divide them. 

The Trans versalis is the internal flat muscle of the abdomen ; it is 
transverse in the direction of its fibres, as is implied in its name. It arises 
from the outer third of Poupart's ligament, from the internal lip of the crest 
of the ilium, its anterior two-thirds ; from the spinous and transverse pro- 
cesses of the lumbar vertebrae, and from the inner surfaces of the six in- 
ferior ribs, indigitating with the diaphragm. Its lower fibres curve down- 
wards, to be inserted, with the lower fibres of the internal oblique, into the 
pectineal line, and form the conjoined tendon. Throughout the rest of 
its extent it is inserted into the crest of the os pubis and linea alba. The 
lower fourth of its aponeurosis passes in front of the rectus to the linea 
alba ; the upper three-fourths with the posterior lamella of the internal 
oblique, behind it. 

The posterior aponeurosis of the transver- 
salis divides into three lamellae ; — anterior, 
which is attached to the bases of the trans- 
verse processes of the lumbar vertebrae ; 
middle, to the apices of the transverse pro- 
cesses ; and posterior, to the apices of the 
spinous processes. The anterior and mid- 
dle lamellae enclose the quadratus lumborum 
muscle ; and the middle and posterior, the 
erector spinae. The union of the posterior 
lamella of the transversalis with the poste- 
rior aponeurosis of the internal oblique, 
serratus posticus inferior, and latissimus 
dorsi, constitutes the lumbar fascia. 

Relations. — By its external surface with 
the internal oblique, the internal surfaces 
of the lower libs, and internal intercostal 
muscles. By its internal surface with the 
transversalis fascia, which separates it from 
the peritoneum, with the psoas magnus, and 
with the lower part of the rectus and pyra- 
midalis. The spermatic cord and oblique 
inguinal hernia pass beneath the lower bor- 
der, but have no direct relation with it. 

* A lateral view of the trunk of the body, showing its muscles, and particularly the 
transversalis abdominis. 1. The costal origin of the latissimus dorsi muscle. 2. The 
serratus magnus. 3. The upper part of the external oblique muscle, divided in the di- 
rection best calculated to show the muscles beneath, without interfering with its indigi- 
tations with the serratus magnus. 4. Two of the external intercostal muscles. 5. Two 
of the internal intercostals. 6. The transversalis muscle. 7. Its posterior aponeurosis. 

8. Its anterior aponeurosis, forming the most posterior layer of the sheath of the rectus. 

9. The lower part of the left rectus, with the aponeurosis of the transversalis passing in 
front. 10. The right rectus muscle. 11. The arched opening left between the lower 
border of the transversalis muscle and Poupart's ligament, through which the spermatic 
cord and hernia pass. 12. The gluteus maximus, and medius, and tensor vaginae femo- 
ris muscles invested by fascia lata. 




216 



MUSCLES OF THE ABDOMEN. 



To dissect the rectus muscle, its sheath should be opened by a vertical 
incision extending from over the cartilages of the lower ribs to the front 
of the os pubis. The sheath may then be dissected off and turned to either 
side ; this is easily done excepting at the lineae transversa?, where a close 
adhesion subsists between the muscle and the external boundary of the 
sheath. The sheath contains the rectus and pyramidalis muscle. 

The Rectus Muscle arises by a flattened tendon from the crest of the 
os pubis, and is inserted into the cartilages of the fifth, sixth, and seventh 
ribs. It is traversed by several tendinous zigzag intersections, called 
lineae transversa?. One of these is usually situated at the umbilicus, two 
above that point, and sometimes one below. They are vestiges of the 
abdominal ribs of reptiles, and very rarely extend completely through the 
muscle. 

Relations. — By its external surface with the anterior lamella of the apo- 
neurosis of the internal oblique, below with the aponeurosis of the trans- 
versalis, and pyramidalis. By its internal surface with the ensiform carti- 
lages of the fifth, sixth, seventh, eighth and ninth ribs, with the posterior 
lamella of the internal oblique, the peritoneum, and the epigastric artery 
and veins. 

The Pyramidalis Muscle arises from the crest of the os pubis in front 
of the rectus, and is inserted into the linea alba at about midway between 
the umbilicus and the os pubis. It is enclosed in the same sheath with 
the rectus, and rests against the lower part of thatmusele. This muscle 
is sometimes wanting. 

The rectus may now be divided across the middle, and the two ends 
drawn aside for the purpose of examining the mode of formation of its 
sheath. 

The sheath of the rectus is formed in front for the upper three-fourths of 
its extent, by the aponeurosis of the external oblique and the anterior la- 
mella of the internal oblique, and behind by the posterior lamella of the 
internal oblique and the aponeurosis of the transversalis. At the com- 
mencement of the lower fourth, the posterior wall of the sheath terminates 
in a thin curved margin, the aponeurosis of the three muscles passing alto- 
gether in front of the rectus. 

The next two muscles can be examined only when the viscera of the 
abdomen are removed. To see the quadratus lumborum, it is also neces- 
sary to divide and draw aside the psoas muscle and the anterior lamella 
of the aponeurosis of the transversalis. 

The Quadratus Lumborum muscle is concealed from view by the an- 
terior lamella of the aponeurosis of the transversalis muscle, which is in- 
serted into the bases of the transverse processes of the lumbar vertebrae. 
When this lamella is divided, the muscle will be seen arising from^ the last 
rib, and from the transverse processes of the four upper lumbar vertebra?. 
It is inserted into the crest of the ilium and ilio-lumbar ligament. If the 
muscle be cut across or removed, the middle lamella of the transversalis 
will be seen attached to the apices of the transverse processes ; the qua- 
dratus being enclosed between the two lamellae as in a sheath. 

Relations. — Enclosed in the sheath formed by the transversalis muscle, 
it is in relation in front, with the kidney, the colon, the psoas magnus and 
the diaphragm. Behind, but also separated by a sheath, with the erector 
spina?. 

The Psoas Parvus arises from the tendinous arches and intervertebral 



DIAPHRAGM. 217 

substance of the last dorsal and first lumbar vertebra, and terminates in a 
long slender tendon which expands inferiorly and is inserted into the ilio- 
pectineal line and eminence. The tendon is continuous by its outer bor- 
der with the iliac fascia. 

Relations. — It rests upon the psoas magnus, and is covered in by the 
peritoneum ; superiorly it passes beneath the ligamentum arcuatum of the 
diaphragm. It is occasionally wanting. 

Diaphragm. — To obtain a good view of this important inspiratory 
muscle, the peritoneum should be dissected from its under surface. It is 
the muscular septum between the thorax and abdomen, and is composed 
of two portions, a greater and a lesser muscle. The greater muscle arises 
from the ensiform cartilage ; from the inner surfaces of the six inferior 
ribs, indigitating with the transversalis ; and from the ligamentum arcua- 
tum externum and internum. From these points, which form the internal 
circumference of the trunk, the fibres converge and are inserted into the 
central tendon. 

The ligamentum arcuatum externum is the upper border of the anterior 
lamella of the aponeurosis of the transversalis : it arches across the origin 
of the quadratus lumborum muscle, and is attached by one extremity to 
the base of the transverse process of the first lumbar vertebra, and by the 
other to the apex and lower margin of the last rib. 

The ligamentum arcuatum internum, or proprium, is a tendinous arch 
thrown across the psoas magnus muscle as it emerges from the chest. It 
is attached by one extremity to the base of the transverse process of the 
first lumbar vertebra, and by the other is continuous with the tendon of 
the lesser muscle opposite the body of the second. 

The tendinous centre of the diaphragm is shaped like a trefoil leaf, of 
which the central leaflet points to the ensiform cartilage, and is the largest ; 
the lateral leaflets, right and left, occupy the corresponding portions of the 
muscle ; the right being the larger and more rounded, and the left smaller 
and lengthened in its form. 

Between the sides of the ensiform cartilage and the cartilages of the 
adjoining ribs, is a small triangular space where the muscular fibres of the 
diaphragm are deficient. This space is closed only by peritoneum on the 
side of the abdomen, and by pleura within the chest. It is therefore a 
weak point, and a portion of the contents of the abdomen might, by vio- 
lent exertion, be forced through it, producing phrenic, or diaphragmatic 
hernia. 

The lesser muscle of the diaphragm takes its origin from the bodies of 
the lumbar vertebrae by two tendons. The right, larger and longer than 
the left, arises from the anterior surface of the bodies of the second, third, 
and fourth vertebrae ; and the left from the side of the second and third. 
The tendons form two large fleshy bellies (crura), which ascend to be in- 
serted into the central tendon. The inner fasciculi of the two crura cross 
each other in front of the aorta, and again diverge to surround the oeso- 
phagus, so as to present the appearance of a figure of eight. The ante- 
rior fasciculus of the decussation is formed by the right cms. 

The openings in the diaphragm are three : one, quadrilateral, in the 
tendinous centre, at the union of the right and middle leaflets, for the 
passage of the inferior vena cava ; a muscular opening of an elliptic shap§ 
formed by the two crura, for the transmission of the oesophagus and pneu* 
mogastric nerves ; and a third, the aortic, which is formed by a tendinous 
19 



218 



MUSCLES OF THE ABDOMEN. 



Fig. 118.* 




arch thrown from the tendon 
of one cms to that of the other, 
beneath which pass the aorta, 
the right vena azygos, and 
thoracic duct. The great 
splanchnic nerves pass through 
openings in the lesser muscle 
on each side, and the lesser 
splanchnic nerves through the 
fibres which arise from the 
ligamentum arcuatum inter- 
num. 

Relations. — By its superior 

surface with the pleurae, the 

pericardium, the heart, and 

the lungs. By its inferior 

surface with the peritoneum; 

on the left with the stomach 

and spleen ; on the right with 

the convexity of the liver ; and behind with the kidneys, the supra-renal 

capsules, the duodenum, and the solar plexus. By its circumference with 

the ribs and intercostal muscles, and with the vertebral column. 

Actions. — The external oblique muscle, acting singly, would draw the 
thorax towards the pelvis, and twist the body to the opposite side. Both 
muscles, acting together, would flex the thorax directly on the pelvis. 
The internal oblique of one side draws the chest downwards and outwards: 
both together bend it directly forwards. Either transversalis muscle, act- 
ing singly, will diminish the size of the abdomen on its own side, and both 
together will constrict the entire cylinder of the cavity. The recti muscles, 
assisted by the pyramidales, flex the thorax upon the chest, and, through 
the medium of the linese transversa?, are enabled to act when their sheath 
is curved inwards by the action of the transversales. The pyramidales 
are tensors of the linea alba. The abdominal are expiratory muscles, and 
the chief agents of expulsion ; by their action the foetus is expelled from 
the uterus, the urine from the bladder, the faeces from the rectum, the bile 
from the gall-bladder, the ingesta from the stomach and bowels in vomit- 
ing, and the mucous and irritating substances from the bronchial tubes, 

* The under or abdominal side of the diaphragm. 1, 2, 3. The greater muscle; the 
figure 1 rests upon the central leaflet of the tendinous centre ; the number 2 on the left 
Or smallest leaflet; and number 3 on the right leaflet. 4. The thin fasciculus which 
arises from the ensiform cartilage; a small triangular space is left on either side of this 
fasciculus, which is closed only by the serous membranes of the abdomen and chest. 
5. The ligamentum arcuatum externum of the left side. 6. The ligamentum arcuatum 
internum. 7. A small arched opening occasionally found, through which the lesser 
splanchnic nerve passes. 8. The right or larger tendon of the lesser muscle ; a mus- 
cular fasciculus from this tendon curves to the left side of the greater muscle between 
the oesophageal and aortic openings. 9. The fourth lumbar vertebra. 10. The left or 
shorter tendon of the lesser muscle. 11. The aortic opening occupied by the aorta, 
which is cut short off. 12. A portion of the oesophagus issuing through the oesophageal 
opening; in this figure the oesophageal opening is tendinous at its anterior part, a struc- 
ture which is not uncommon. 13. The opening for the inferior vena cava, in the ten- 
dinous centre of the diaphragm. 14. The psoas magnus muscle passing beneath the 
ligamentum arcuatum internum ; it has been removed on the opposite side to show the 
arch more distinctly. 15. The quadratus lumborum passing beneath the ligamentum 
arcuatum externum ; this muscle has also been removed on the left side. 



MUSCLES OF THE PERINEUM. 219 

trachea, and nasal passages, during coughing and sneezing. To produce 
these efforts they all act together. Their violent and continued action 
pro<|uces hernia ; and, acting spasmodically, they may occasion rupture 
of the viscera. The quadratus lumborum draws the last rib downwards, 
and is an expiratory muscle ; it also serves to bend the vertebral column 
to one or the other side. The psoas parvus is a tensor of the iliac fascia, 
and, taking its fixed origin from below, it may assist in flexing the verte- 
bral column forwards. The diaphragm is an inspiratory muscle, and the 
sole agent in tranquil inspiration. When in action, the muscle is drawn 
downwards, its plane being rendered oblique from the level of the ensi- 
form cartilage, to that of the upper lumbar vertebra. During relaxation 
it is convex, and encroaches considerably on the cavity of the chest, par- 
ticularly at the sides, where it corresponds with the lungs. It assists the 
abdominal muscles powerfully in expulsion, every act of that kind being 
preceded or accompanied by a deep inspiration. Spasmodic action of the 
diaphragm produces hiccough and sobbing, and its rapid alternation of 
contraction and relaxation, combined with laryngeal and facial movements, 
laughing and crying. 

MUSCLES OF THE PERINEUM. 

The muscles of the perineum are situated in the outlet of the pelvis, and 
consist of two groups, one of which belongs especially to the organs of 
generation and urethra, the other to the termination of the alimentary canal. 
To these may be added the only pair of muscles which is proper to the 
pelvis, the coccygeus. The muscles of the perineal region in the male^ 
are the 

Accelerator urinae, Sphincter ani, 

Erector penis, Levator ani, 

Compressor urethral, Coccygeus., 
Transversus perinei, 

Dissection. — To dissect the perineum, the subject should be fixed in 
the position for lithotomy, that is, the hands should be bound to the soles 
of the feet, and the knees kept apart: An. easier plan is the drawing of 
the feet upwards by means of a cord passed through a hook in the ceiling. 
Both of these plans of preparation have for their object the full exposure 
of the perineum. And as this is a dissection which demands some degree 
of delicacy and nice manipulation, a strong light should be thrown upon 
the part. Having fixed the subject, and drawn the scrotum upwards by 
means of a string or hook, carry an incision from the base of the scrotum 
along the ramus of the pubes and ischium and tuberosity of the ischium, 
to a point parallel with the apex of the coccyx ; then describe a curve 
over the coccyx to the same point on the opposite side, and continue the 
incision onwards along the opposite tuberosity, and along the ramus of the 
ischium and of the pubes, to the opposite side of the scrotum, where the 
two extremities may be connected by a transverse incision. This incision 
will completely surround the perineum, following very nearly the outline 
of its boundaries. Now let the student dissect off the integument care- 
fully from the whole of the included space, and he will expose the fatty 
cellular structure of the common superficial fascia, which exactly resembles 
the superficial fascia in every other situation. The common superficial 



220 MUSCLES OF THE PERINEUM. 

fascia is then to be removed to the same extent, exposing the superficial 
perineal fascia. This layer is also to be turned aside, when the muscles 
of the genital region of the perineum will be brought into view. 

The Acceleratores URiNiE (bulbo-cavernosus) arise from a tendinous 
point in the centre of the perineum and from the fibrous raphe of the two 
muscles. From these origins the fibres diverge, like the plumes of a pen ; 
the posterior fibres to be inserted into the ramus of the pubes and ischium ; 
the middle to encircle the corpus spongiosum, and meet upon its upper 
side ; and the anterior to spread out upon the corpus cavernosum on each 
side, and be inserted, partly into its fibrous structure, and partly into the 
fascia of the penis. The posterior and middle insertions of these muscles 
are best seen, by carefully raising one muscle from the corpus spongiosum 
and tracing its fibres. 

• Relations. — By their superficial surface with the superficial perineal 
fascia, the dartos, the superficial vessels and nerves of the perineum, and 
on each side with the erector penis. By their deep surface with the corpus 
spongiosum and bulb of the urethra. 

The Erector Penis (ischio-cavernosus) arises from the ramus and tu- 
berosity of the ischium, and curves around the root of the penis, to be in- 
serted into the upper surface of the corpus cavernosum, where it is con- 
tinuous with a strong fascia winch covers the dorsum of the organ, the 
fascia penis. 

Relations. — By its superficial surface with the superficial perineal fascia, 
the dartos, and the superficial perineal vessels and nerve. By its deep 
surface with the corpus cavernosum penis. 

The Compressor Urethje (Wilson's and Guthrie's muscles), consists 
of two portions ; one of which is transverse in its direction, and passes in- 
wards, to embrace the membranous urethra ; the other is perpendicular, 
and descends from the pubes. The transverse portion, particularly de- 
scribed by Mr. Guthrie, arises by a narrow tendinous point, from the upper 
part of the ramus of the ischium, on each side, and divides into two fasci- 
culi, which pass inwards and slightly upwards, and embrace the membra- 
nous portion of the urethra and Cowper's glands. As they pass towards 
the urethra, they spread out and become fan-shaped, and are inserted into 
a tendinous raphe upon the upper and lower surfaces of the urethra, ex- 
tending from the apex of the prostate gland, to which they are attached 
posteriorly, to the bulbous portion of the urethra, w T ith which they are con- 
nected in front. When seen from above, these portions resemble two fans, 
connected by their expanded border along the middle line of the mem- 
branous urethra, from the prostate to the bulbous portion of the urethra. 
The same appearance is obtained by viewing them from below. 

The perpendicular portion* described by Mr. Wilson, arises by two ten- 
dinous points from the inner surface of the arch of the pubes, on each side 
of, and close to, the symphysis. The tendinous origins soon become 
muscular, and descend perpendicularly, to be inserted into the upper fas- 
ciculus of the transverse portion of the muscle ; so that it is not a distinct 
muscle surrounding the membranous portion of the urethra, and support- 

* Mr. Tyrrell, who made many careful dissections of the muscles of the perineum, 
did not observe tin's portion of the muscle ; he considers Wilson's muscle (with some 
other anatomists) to be the anterior fibres of the levator ani, not uniting beneath the 
urethra, as described by Mr. Wilson; but inserted into a portion of the pelvic fascia 
situated between the prostate gland and rectum, the recto-vesical fascia. 



TRANSVERSUS PERINEI. 



221 



mg it as in a sling, as described by Mr. Wilson, but merely an upper 
origin of the transverse muscle. 

Fig. 119* 




The compressor urethras may be considered either as two symmetrical 
muscles meeting at the raphe, or as a single muscle : I have adopted the 
latter course in the above description, as appearing to me the more con- 
sistent with the general connexions of the muscle, and with its actions. 

The Transversus Perinei arises from the tuberosity of the ischium 
on each side, and is inserted into the central tendinous point of the 
perineum, f 

Relations. — By its superficial surface with the superficial perineal fascia, 
and superficial perineal artery. By its deep surface with the deep perineal 
fascia, and internal pudic artery and veins. By its posterior border it is 
in relation with that portion of the superficial perineal fascia which passes 
back to become continuous with the deep fascia. 

To dissect the compressor urethrce, the whole of the preceding muscles 
should be removed, so as to render the glistening surface of the deep peri- 
neal fascia quite apparent. The anterior layer of .the fascia should then 
be carefully dissected away, and the corpus spongiosum penis divided 
through its middle, separated from the corpus cavernosum, and drawn 
forwards, to put the membranous portion of the urethra, upon which the 
muscle is spread out, on the stretch. The muscle is, however, better 
seen in a dissection made from within the pelvis, after having turned 

* The muscles of the perineum. 1. The acceleratores urirue muscles; the figure rests 
upon the corpus spongiosum penis. 2. The corpus cavernosum of one side. 3. The 
erector penis of one side. 4. The transversus perinei of one side. 5. The triangular 
space through which the deep perineal fascia is seen. 6. The sphincter ani ; its ante- 
rior extremity is cut off. 7. The levator ani of the left side ; the deep space between 
the tuberosity of the ischium (8) and the anus, is the ischio-rectal fossa; the same fossa 
is seen upon the opposite side. 9. The spine of the ischium. 10. The left coccygeus 
muscle. The boundaries of the perineum are well seen in this engraving. 

j- I have twice dissected a perineum in which the transversus perinei was of large 
size, and spread out as it approached the middle line, so as to become fan-shaped. The 
posterior fibres were continuous with those of the muscle of the opposite side ; but the 
anterior were prolonged forwards upon the bulb and corpus spongiosum of the urethra, 
as far as the middle of the penis, forming a broad layer which usurped the place and 
office of the accelerator urina3. 

19* 



222 MUSCLES OF THE PERINEUM. 

down the bladder from its attachment to the os pubis, and removed a 
plexus of veins and the posterior layer of the deep perineal fascia. 

The Sphincter Ani is a thin and elliptical plane of muscle closely ad- 
herent to the integument, and surrounding the opening of the anus. It 
arises posteriorly in the superficial fascia around the coccyx, and by a 
fibrous raphe from the apex of that bone ; and is inserted anteriorly into 
the tendinous centre of the perineum, and into the raphe of the integument, 
nearly as far forwards as the commencement of the scrotum. 

Relations. — By its superficial surface with the integument. By its deep 
surface with the internal sphincter, the levator ani, the cellular tissue and 
fat in the ischio-rectal fossa, and in front with the superficial perineal 
fascia. 

The Sphincter Ani Internus is a muscular ring embracing the ex- 
tremity of the intestine, and formed by an aggregation of the circular 
fibres of the rectum. 

Part of the levator ani may be seen during the dissection of the anal 
portion of the perineum, by removing the fat which surrounds the termi- 
nation of the rectum in the ischio-rectal fossa. But to study the entire 
muscle, a lateral section of the pelvis must be made by sawing through 
the pubes a little to one side of the symphysis, separating the bones 
behind at the sacro-iliac symphysis, and turning down the bladder and 
rectum. The pelvic fascia is then to be carefully raised, beginning at the 
base of the bladder and proceeding upwards, until the whole extent of 
the muscle is exposed. 

The Levator Ani is a thin plane of muscular fibres, situated on each 
side of the pelvis. The muscle arises from the inner surface of the os 
pubis, from the spine of the ischium, and between those points from the 
angle of division between the obturator and the pelvic fascia. Its fibres 
descend, to be inserted, into the extremity of the coccyx, into a fibrous 
raphe in front of that bone, into the lower part of the rectum, base of the 
bladder, and prostate gland. 

In the female, this muscle is inserted into the coccyx and fibrous raphe, 
lower part of the rectum and vagina. 

Relations. — By its external or perineal surface, with a thin layer of 
fascia, by which, and by the obturator fascia, it is separated from the ob- 
turator internus muscle ; with the fat in the ischio-rectal fossa, the deep 
perineal fascia, the levator ani, and posteriorly with the gluteus maximus. 
By its internal or pelvic surface, with the pelvic fascia, which separates it 
from the viscera of the pelvis and peritoneum. 

The Coccygeus Muscle is a tendino-muscular layer of triangular form. 
It arises from the spine of the ischium, and is inserted into the side of the 
coccyx and lower part of the sacrum. 

Relations. — By its internal or pelvic surface, with the rectum ; by its 
external surface, with the lesser and greater sacro-ischiatic ligaments. 

The muscles of the perineum in the female are the same a"s in the male, 
and have received analogous names. They are smaller in size, and are 
modified to suit the different form of the organs ; they are — 

Constrictor vaginse, Sphincter ani, 

Erector clitoridis, Levator ani, 

Transversus perinei, Coccygeus. 
Compressor urethra?, 



MUSCLES OF THE UPPER EXTREMITY. 223 

The Constrictor vagince is analogous to the acceleratores urinae ; it is 
continuous, posteriorly, with the sphincter ani, interlacing with its fibres, 
and is inserted, anteriorly, into the sides of the corpora cavernosa, and 
fascia of the clitoris. 

The Transversus perinei is inserted into the side of the constrictor vagi- 
nae, and the levator ani into the side of the vagina. 

The other muscles are precisely similar in their attachments to those in 
the male. 

Actions. — The acceleratores urinae being continuous at the middle line, 
and attached on each side to the bone, by means of their posterior fibres, 
will support the bulbous portion of the urethra, and acting suddenly, will 
propel the semen, or the last drops of urine, from the canal. The poste- 
rior and middle fibres, according to Krause,* contribute towards the erec- 
tion of the corpus spongiosum, by producing compression upon the venous 
structure of the bulb ; and the anterior fibres, according to Tyrrell, f assist 
in the erection of the entire organ by compressing the vena dorsalis, by 
means of their insertion into the fascia penis. The erector penis becomes 
entitled to its name from spreading out upon the dorsum of the organ, 
into a membranous expansion, (fascia penis,) which, according to Krause, 
compresses the dorsal vein during the action of the muscle, and especially 
after the erection of the organ has commenced. The transverse muscles 
serve to steady the tendinous centre, that the muscles attached to it may 
obtain a firm point of support. According to Cruveilhier, they draw the 
anus backwards during the expulsion of the faeces, and antagonize the 
levatores ani, which carry the anus forwards. The compressor urethra?, 
taking its fixed point from the ramus of the ischium at each side, can, 
says Mr. Guthrie, " compress the urethra so as to close it ; I conceive 
completely, after the manner of a sphincter." The transverse portion will 
also have a tendency to draw the urethra downwards, whilst the perpen- 
dicular portion will draw it upwards towards the os pubis. The inferior 
fasciculus of the transverse muscle, enclosing Cowper's glands, will assist 
those bodies in evacuating their secretion. The external sphincter, being 
a cutaneous muscle, contracts the integument around the anus, and by its 
attachment to the tendinous centre, and to the point of the coccyx, assists 
Ihe levator ani in giving support to the opening during expulsive efforts. 
The internal sphincter contracts the extremity of the cylinder of the intes- 
tine. The use of the levator ani is expressed in its name. It is the an- 
tagonist of the diaphragm and the rest of the expulsory muscles, and 
series to support the rectum and vagina during their expulsive efforts. 
The levator ani acts in unison with the diaphragm, and rises and falls like 
that muscle in forcible respiration. Yielding to the propulsive action of 
the abdominal muscles, it enables the outlet of the pelvis to bear a greater 
force than a resisting structure, and on the remission of such action it re- 
stores the perineum to its original form. The coccygei muscles restore 
the coccyx "to its natural position, after it has been pressed backwards 
during defaecation or during parturition. 

MUSCLES OF THE UPPER EXTREMITY. 

The muscles of the upper extremity may be arranged into groups cor- 
responding with the different regions of the limb, thus : 

* Miiller, Archiv. fur Anatornie, Physiologie, &c. 1837. 
f Lectures in the College of Surgeons. 1839. 



224 



MUSCLES OF THE UPPER EXTREMITY. 



Anterior Thoracic Region. 
Pectoralis major, 
Pectoralis minor, 
Subclavius. 

Anterior Scapular Region. 
Subscapularis. 



Lateral Thoracic Region. 
Serratus magnus. 



Posterior Scapular Region., 

Supra-spinatus, 
Infra- spinatus, 
Teres minor, 
Teres major. 



Acromial Region. 



Deltoid. 



Anterior Humeral Region. 

Coraco-brachialis, 
Biceps, 
Brachialis anticus. 

Anterior Brachial Region. 
Superficial Layer. 

Pronator radii teres, ' 
Flexor carpi radialis, 
Palmaris longus, 
Flexor sublimis digitorum, 
Flexor carpi ulnaris. 



Deep Layer. 

Flexor profundus digitorum, 
Flexor longus pollicis, 
Pronator quadratus. 



Radial Region (Thenar). 

Abductor pollicis, 
Flexor ossis metacarpi 

(opponens), 
Flexor brevis pollicis, 
Adductor pollicis. 



Posterior Humeral Region. 
Triceps. 



Postenor Brachial Region. 
Superficial Layer. 

Supinator longus, 
Extensor carpi radialis longior, 
Extensor carpi radialis brevior, 
Extensor communis digitorum, 
Extensor minimi digiti, 
Extensor carpi ulnaris, 
Anconeus. 

Deep Layer. 

Supinator brevis, 
Extensor ossis metacarpi pollicis, 
Extensor primi internodii pollicis, 
Extensor secundi internodii pollicis 
Extensor indicis. . 

Hand. 

Ulnar Region (Hypothenar). 

Palmaris brevis, 
Abductor minimi digiti. 
Flexor brevis minimi digiti, 
Adductor minimi digiti. 



Palmar Region. 
Lumbricales, 
Interossei palmares, 
Interossei dorsales. 



Anterior Thoracic Region. 

Pectoralis major, 
Pectoralis minor, 
Subclavius. 



PECTORALIS MAJOR AND MINOR. 225 

Dissection. — Make an incision along the line of the clavicle, from the 
upper part of the sternum to the acromion process ; a second along the 
lower border of the great pectoral muscle, from the lower end of the ster- 
num to the insertion of its tendon into the humerus, and connect the two 
by a third, carried longitudinally along the middle of the sternum. The 
integument and superficial fascia are to be dissected together from off the 
fibres of the muscle, and always in the direction of their course. For this 
purpose the dissector, if he have the right arm, will commence with the 
lower angle of the flap ; if the left, with the upper angle. He will thus 
expose the pectoralis major muscle in its whole extent. 

The Pectoralis Major muscle arises from the sternal two-thirds of 
the clavicle, from one half the breadth of the sternum its whole length, 
from the cartilages of all the true ribs, excepting the first and last, and 
from the aponeurosis of the external oblique muscle of the abdomen. It 
is inserted by a broad Jendon into the anterior bicipital ridge of the hu- 
merus. 

That portion of the muscle which arises from the clavicle is separated 
from that connected with the sternum by a distinct cellular interspace ; 
hence we speak of the clavicular portion and sternal portion of the pecto- 
ralis major. The fibres from this very extensive origin converge towards 
a narrow insertion, giving the muscle a radiated appearance. But there 
is a peculiarity about the formation of its tendon which must be carefully 
noted. The whole of the lower border is folded inwards upon the upper 
portion, so that the tendon is doubled upon itself. Another peculiarity 
results from this arrangement : the fibres of the upper portion of the muscle 
are inserted into the lower part of the bicipital ridge ; and those of the 
lower portion, into the upper part. 

Relations. — By its external surface with the fibres of origin of the 
platysma myoides, the mammary gland, the superficial fascia and inte- 
gument. By its internal surface, on the thorax, with the clavicle, the 
sternum, the costal cartilages, intercostal muscles, subclavius, pectoralis 
minor, and serratus magnus ; in the axilla," with the axillary vessels and 
glands. By its external border with the deltoid, from which it is separated 
above by a cellular interspace lodging the cephalic vein and the descend- 
ing branch of the thoracico-acromialis artery. Its lower border forms the 
anterior boundary of the axillary space. 

The pectoralis major is now to be removed by dividing its fibres along 
the lower border of the clavicle, and then carrying the incision perpendi- 
cularly downwards, parallel to the sternum, and at about three inches 
from its border. Divide some loose cellular tissue, and several small 
branches of the thoracic arteries, and reflect the muscle outwards. We 
thus bring into view a region of considerable interest, in the middle of 
which is situated the pectoralis minor. 

The Pectoralis Minor arises by three digitations from the third, fourth, 
and fifth ribs, and is inserted into the anterior border of the coracoid pro- 
cess of the scapula by a broad tendon. 

Relations. — By its anterior surface with the pectoralis major and supe- 
rior thoracic vessels and nerves. By its posterior surface with the ribs, 
the intercostal muscles, serratus magnus, axillary space, and axillary 
vessels and nerves. Its upper border forms the lower boundary of a trian- 
gular space bounded above by the costo-coracoid membrane, and inter- 

p 



*• 



226 ANTERIOR SCAPULAR REGION. 

nally by the ribs. In this space are found the axillary vessels and nerves, 
and in it the subclavian artery may be tied below the clavicle. 

The Subclavius muscle arises by a round tendon from the cartilage 
of the first rib, and is inserted into the under surface of the clavicle. This 
muscle is concealed by the costo-coraeoid membrane, an extension of the 
deep cervical fascia, by which it is invested. 

Relations. — By its upper surface with the clavicle. By the lower with 
the subclavian artery and vein and brachial plexus, which separate it from 
the first rib. In front with the pectoralis major, the costo-coracoid mem- 
brane being interposed. 

Actions. — The pectoralis major draws the arm against the thorax, while 
its upper fibres assist the upper part of the trapezius in raising the shoulder 
as in supporting weights. The lower fibres depress the shoulder with the 
aid of the latissimus dorsi. Taking its fixed point from the shoulder, 
the pectoralis major assists the pectoralis minor, subclavius, and serratus 
magnus, in drawing up and expanding the chest. The pectoralis minor, 
in addition to this action, draws upon the coracoid process, and assists in 
rotating the scapula upon the chest. The subclavius draws the clavicle 
downwards and forwards, and thereby assists in steadying the shoulder. 
All the muscles of this group are agents in forced respiration, but are in- 
capable of acting until the shoulders are fixed. 

Lateral Thoracic Region. 
Serratus magnus. 

The Serratus Magnus (serratus, indented like the edge of a saw), 
arises by fleshy serrations from the nine upper ribs excepting the first, and 
extends backwards upon the side of the chest, to be inserted into the whole 
length of the base of the scapula upon its anterior aspect. In structure 
the muscle is composed of three portions, a superior portion formed by 
two serrations attached to the second rib, and inserted into the inner sur- 
face of the superior angle of the scapula, a middle portion composed of 
the serrations connected with the third and fourth ribs, and inserted into 
the greater part of Ihe posterior border, and an inferior portion consisting 
of the last five serrations which in digitate with the obliquus externus and 
form a thick muscular fasciculus which is inserted into the scapula near its 
inferior angle. 

Relations. — By its superficial surface with the pectoralis major and mi- 
nor, the subscapulars, and the axillary vessels and nerves. By its deep 
surface with the ribs and intercostal muscles, to which it is connected b) 1 
an extremely loose cellular tissue. 

Actions. — The serratus magnus is the great external inspiratory muscle, 
raising the ribs when the shoulders are fixed, and thereby increasing the 
cavity of the chest. Acting upon the scapula, it draws the shoulder for- 
wards, as we see to be the case in diseased lungs, where the chest has 
become almost fixed from apprehension of the expanding action of the 
respiratory muscles. 

interior Scapular Region. 
Subscapularis. 

The Subscapularis muscle arises from the whole of the under surface 
of the scapula excepting the superior and inferior angle, and terminates by 



POSTERIOR SCAPULAR REGION. 227 

a broad and thick tendon, which is inserted into the lesser tuberosity of the 
humerus. The substance of the muscle is traversed by several intersecting 
membranous layers from which muscular fibres arise, the intersections 
being attached to the ridges on the surface of the scapula. Its tendon 
forms part of the capsule of the joint, glides over a large bursa which 
separates it from the base of the coracoid process, and is lined by a pro- 
longation of the synovial membrane of the articulation. 

Relations. — By its anterior surface with the serratus magnus, coraco- 
brachialis, and axillary vessels and nerves. By its posterior surface with 
the scapula, the subscapular vessels and nerves, and the shoulder joint. 

Action. — It rotates the head of the humerus inwards, and is a powerful 
defence to the joint. When the arm is raised, it draws the humerus 
downwards. 

Posterior Scapular Region. 

Supra-spinatus, Teres minor, 

Infra-spinatus, Teres major. 

The Supra-spinatus muscle (supra, above ; spina, the spine) arises 
from the whole of the supra-spinous fossa, and is inserted into the upper- 
most depression on the great tuberosity of the humerus. The tendon of 
this muscle cannot be well seen until the acromion process is removed. 

Relations. — By its upper surface, with the trapezius, the clavicle, acro- 
mion, and coraco-acromion ligament. From the trapezius it is separated 
by a strong fascia. By its lower surface, with the supra-spinous fossa, the 
supra-scapular vessels and nerve, and the upper part of the shoulder joint, 
forming part of the capsular ligament. 

The Infra-spinatus {infra, beneath ; spina, the spine) is covered in by 
a layer of tendinous fascia, which must be removed before the fibres of the 
muscle can be seen, the deltoid muscle having been previously turned 
down from its scapular origin. It arises from the whole of the infra-spinous 
fossa, and from the fascia above-mentioned, and is inserted into the middle 
depression upon the greater tuberosity of the humerus. 

Relations. — By its posterior surface, with the deltoid, latissimus dorsi 
and integument. By its anterior surface, with the infra-spinous fossa, su- 
perior and dorsal scapular vessels, and shoulder joint ; its tendon being 
lined by a prolongation from the synovial membrane. By its upper border, 
it is in relation with the spine of the scapula, and by the lower, with the 
teres minor, with which it is closely united. * 

The Teres Minor muscle (teres, round) arises from the middle third 
of the inferior border of the scapula, and is inserted into the lower depres- 
sion on the great tuberosity of the humerus. The tendons of these three 
muscles, with that of the subscapularis, are in immediate contact with the 
shoulder joint, and form part of its ligamentous capsule, thereby preserving 
the solidity of the articulation. They are therefore the structures most 
frequently ruptured in dislocation of the head of the humerus. 

Relations. — By its posterior surface, with the deltoid, latissimus dorsi 
and integument. By its anterior surface, with the inferior border, and 
part of the dorsum of the scapula, the dorsalis scapulae vessels, scapular 
head of the triceps, and shoulder joint. By its upper border, with the 
infra-spinatus ; and by the lower, with the latissimus dorsi, teres major, 
and long head of the triceps. 



228 



ACROMIAL REGION. 



The Teres Major muscle arises from the lower third of the inferior 
border of the scapula, encroaching a little upon its dorsal aspect, and is 
inserted into the posterior bicipital ridge. Its tendon lies immediately 
behind that of the latissimus dorsi, from which it is separated by a syno- 
vial membrane. 

Relations.— By its posterior surface, with the latissimus dorsi, scapular 
head of the triceps and integument. By its anterior surface, with the 
subscapularis, latissimus dorsi, coraco-brachialis, short head of the biceps, 
axillary vessels, and branches of the brachial plexus. By its upper border, 
it is in relation with the teres minor, from which it is separated by the 
scapular head of the triceps ; and by the lower, it forms with the latissimus 
dorsi, the lower and posterior border of the axilla. 

A large triangular space exists between the two teres muscles, which is 
divided into two minor spaces by the long head of the triceps. 

Actions. — The supra-spinatus raises the arm from the side ; but only 
feebly, from the disadvantageous direction of the force. The infra- spinatus 
and teres minor are rotators of the head of the humerus outwards. The 
most important use of these three^niuscles is the protection of the joint, 
and defence against displacement of the head of the humerus, in which 
action they co-operate with the subscapularis. The teres major combines, 
with the latissimus dorsi, in rotating the arm inwards, and at the same 
time carrying it towards the side, and somewhat backwards. 

Acromial Region. 
Deltoid. 

The convexity of the shoulder is formed by a large triangular muscle, 
the deltoid (a, delta ; sidoc:, resemblance), which arises from the outer third 
of the clavicle, from the acromion process, and from the whole length of 
the spine of the scapula. The fibres from this broad origin converge to 
the middle of the outer side of the humerus, where they are inserted into 
a rough triangular elevation. This muscle is remarkable for its coarse 
texture, and for its numerous tendinous intersections, from which mus- 
cular fibres arise. The deltoid muscle may now, be cut away from its 
origin, and turned down, for the purpose of bringing into view the 
muscles and tendons placed immediately around the shoulder joint. In 
so doing, a large bursa will be seen between the under surface of the 
muscle and the head of the humerus. 

Relations. — By its superficial surface, with a thin aponeurotic fascia, a 
few fibres of the platysma myoides, the superficial fascia and integument. 
By its deep surface, with the shoulder joint, from which it is separated by 
a thin tendinous fascia, and by a synovial bursa ; with the coraco-acromial 
ligament, coracoid process, pectoralis minor, coraco-brachialis, both heads 
of the biceps, tendon of the pectoralis major, tendon of the supra-spinatus, 
infra-spinatus, teres minor, teres major, scapular and external head of the 
triceps, the circumflex vessels anterior and posterior, and humerus. By 
its anterior border, with the external border of the pectoralis major, from 
which it is separated by a cellular interspace, lodging the cephalic vein 
and descending branch of the thoracico-acromialis artery. Its posterior 
border is thin and tendinous above, where it is connected with the apo- 
neurotic covering of the infra-spinatus muscle, and thick below. 

Actions. — The deltoid is the elevator muscle of the arm in a direct 



ANTERIOR HUMERAL REGION. 



229 




line, and by means of its extensive origin can carry the arm forwards or 
backwards, so as to range with the hand a considerable segment of a large 
circle. The arm, raised by the deltoid, is a good Fig 120 * 

illustration of a lever of the third power, so common 
in the animal machine, by which velocity is gained 
at the expense of power. In this lever, the weight 
(hand) is at one extremity, the fulcrum (the glenoid 
cavity) at the opposite end, and the power (the in- 
sertion of the muscle) between the two, but nearer 
to the fulcrum than to the weight. 

Anterior Humeral Region. 

Coraco-brachialis, 
Biceps, 
Brachialis anticus. 

Dissection. — These muscles are exposed, on the 
removal of the integument and fascia from the ante- 
rior half of the upper arm, and the clearing away of 
the cellular tissue. 

The Coraco-Brachialis, a name composed of its 
points of origin and insertion, arises from the cora- 
coid process in common with the short head of the 
biceps ; and is inserted into a rough line on the 
inner side of the middle of the humerus. 

Relations. — By its anterior surface with the deltoid, and pectoralis 
major. By its posterior surface, with the shoulder joint, the humerus, 
subscapularis, teres major, latissimus dorsi, short head of the triceps, and 
anterior circumflex vessels. By its internal border with the axillary and 
brachial vessels and nerves, particularly with the median and external 
cutaneous nerve, by the latter of which it is pierced. By the external 
border with the short head of the biceps and brachialis anticus. 

The Biceps (bis — xstpaXou, two heads) arises by two tendons, one the 
short head, from the coracoid process in common with the coraco-brachi- 
alis ; the other the long head, from the upper part of the glenoid cavity. 
The muscle is inserted by a rounded tendon, into the tubercle of the ra- 
dius. The long head, a long slender tendon, passes through the capsular 
ligament of the shoulder joint enclosed in a sheath of the synovial mem- 
brane ; after leaving the cavity of the joint, it is lodged in the deep groove 
that separates the two tuberosities of the humerus, the bicipital groove. 
A small synovial bursa is interposed between the tendon of insertion, and 
the tubercle of the radius. At the bend of the elbow, the tendon of the 
biceps gives off from its inner side a broad tendinous band, which protects 
the brachial artery, and is continuous with the fascia of the fore-arm. 

Relations. — By its anterior surface with the deltoid, pectoralis major, 
superficial and deep fascia and integument. By its posterior surface the 

• The muscles of the anterior aspect of the upper arm. 1. The coracoid process of 
the scapula. 2. The coraco-clavicular ligament (trapezoid), passing upwards to the 
scapular end of the clavicle. 3. The coraco-acromial ligament, passing outwards to the 
acromion. 4. The subscapularis muscle. 5. The teres major ; the triangular space 
above this muscle is that through which the dorsalis scapulte vessels pass. 6. The 
coraco-brachialis. 7. The biceps. 8. The upper end of the radius. 9. The brachialis 
anticus ; a portion of the muscle is seen on the outer side of the tendon of the biceps 
10. The internal head of the triceps. 

20 



230 



POSTERIOR HUMERAL REGIOft. 



short head rests upon the subscapulars, from which it is separated by a 
bursa. In the rest of its extent the muscle is in relation with the humerus, 
the teres major, latissimus dorsi, and brachialis anticus ; from the latter it 
is separated by the external cutaneous nerve. By its inner border with 
the coraco-brachialis, brachial artery and veins, and median nerve ; the 
brachial vessels crossing its tendon at the bend of the elbow. By its 
outer border with the deltoid and supinator longus. 

The Brachialis Anticus is a broad muscle covering the whole of the 
anterior surface of the lower part of the humerus ; it arises by two fleshy 
serrations from the depressions on either side of the insertion of the del- 
toid, from the anterior surface of the humerus, and from the intermuscular 
septa attached to the condyloid ridges. Its- fibres converge to be inserted 
into the coronoid process of the ulna. 

Relations. — By its anterior surface with the biceps, external cutaneous 
nerve, brachial artery and veins, and median nerve. By its posterior sur- 
face with the humerus, anterior ligament of the elbow joint, and inter- 
muscular aponeurosis. The latter separates it from the triceps. By its 
external border with the supinator longus, extensor carpi radialis longior, 
musculo-spiral nerve, and recurrent radial artery. By its internal border 
with the intermuscular aponeurosis, which separates it from the triceps 
and ulnar nerve, and with the pronator radii teres. 

Actions. — The coraco-brachialis draws the humerus inwards, and assists 
in flexing it upon the scapula. The biceps and brachialis anticus are 
flexors of the fore-arm, and the former a supinator. The brachialis anticus 
is a powerful protection to the elbow joint. 

Fig. 121* Posterior Humeral Region. 

Triceps extensor cubiti. 

Dissection. — Remove the integument and fascia 
from the posterior aspect of the upper arm. 

The Triceps (<rpsTg xs<paXrxi, three heads) arises 
by three heads. Considered in relation to their 
length, these heads have been named long, short, 
and middle; and in reference to their position, 
internal, external, and middle; the term middle, 
in the former case, referring to the external head, 
and in the latter case to the long head. This has 
given rise to much confusion and misunderstand- 
ing. I shall, therefore, confine myself to the de- 
signations derived from their relations. The ex- 
ternal head arises from the humerus, commencing 
immediately below the insertion of the teres minor, 
and from the intermuscular septum attached to the 
external condyloid ridge. The internal head 
(short) arises from the humerus, commencing im- 
mediately below the insertion of the teres major, 
and from the intermuscular septum attached to 
the internal condyloid ridge. The scapular head 
(long) lies between the two others, and arises 
from the upper third of the inferior border of the 

* A posterior view of the upper arm, showing the triceps muscle. 1. Its external 
head. 2. Its long, or scapular head. 3. Its internal, or short head. 4. The olecranon 
process of the ulna. 5. The radius. 6. The capsular ligament of the shoulder joint. 




ANTERIOR BRACHIAL REGION. 



231 



Fig. 122 * 



scapula. The three heads unite to form a broad muscle, which is inserted 
by an aponeurotic tendon into the olecranon process of the ulna ; a small 
bursa is situated between its tendon and the upper part of the olecranon. 

The scapular head of the triceps passes between the teres minor and 
major, and divides the triangular space between those two muscles into 
two smaller spaces, one of which is triangular, the other quadrangular. 
The triangular space is bounded by the teres minor, teres major, and 
scapular head of the triceps ; it gives passage to the dorsalis scapulae ar- 
tery and veins. The quadrangular space is bounded on three sides by 
the three preceding muscles, and on the fourth by the humerus. Through 
this space pass the posterior circumflex artery and veins, and circumflex 
nerve. 

A few of the deep fibres of the triceps, attached above to the humerus 
and below to the capsule of the elbow joint, have been named sub-anco- 
neus ; they are analogous to the sub-crureus. 

Relations. — By its posterior surface with the deep and superficial fascia 
and integument. By its anterior surface with the superior profunda artery, 
musculo-spiral nerve, humerus, intermuscular aponeuroses which separate 
it from the brachialis anticus, and with the elbow joint. The scapular 
head is in relation posteriorly with the deltoid and teres minor ; anteriorly 
with the subscapularis, teres major, and latissimus dorsi ; and externally 
w T ith the posterior circumflex vessels and nerve. 

Actions. — The triceps is an extensor of the fore- 
arm. 

Anterior Brachial Region. 

Superficial Layer. 
Pronator radii teres, 
Flexor carpi radialis, 
Pal maris longus, 
Flexor sublimis digitorum, 
Flexor carpi ulnaris. 

Dissection. — These muscles are brought into view 
by making an incision through the integument along 
the middle line of the fore-arm, crossing each extre- 
mity by a transverse incision, and turning aside the 
flaps. The superficial and deep fascia are then to be 
removed. 

The Pronator Radii Teres arises by two heads ; 
one from the inner condyle of the humerus, fascia of 
the fore-arm, and intermuscular aponeurosis ; the 
other from the coronoid process of the ulna ; the me- 
dian nerve passing between them. Its tendon is flat 
and inserted into the middle third of the oblique ridge 
of the radius. The two heads of this muscle are best 
examined by cutting through that which arises from 
the inner condyle, and turning it aside. The second 
head will then be seen with the median nerve lying 
across it. , 

* Superficial layer of the muscles of the fore-arm. 1. The lower part of the biceps, 
with its tendon. 2. A part of the brachialis anticus, seen beneath the biceps. 3. Apart 
of the triceps. 4. The pronator radii teres. 5. The flexor carpi radialis. 6. The pal- 




232 FLEXOR CARPI RADIAL1S. 

Relations. — By its anterior surface with the fascia of the fore-arm, the 
supinator longus, extensor carpi radialis longior and brevior, radial artery 
and veins, and radial nerve. By its posterior surface with the brachialis 
anticus, flexor sublimis digitorum, the ulnar artery and veins, and the me- 
dian nerve after it has passed between the two heads of the muscle. By 
its upper border it forms the inner boundary of the triangular space, in 
which the termination of the brachial artery is situated. By its lower 
border it is in relation with the flexor carpi radialis. 

The Flexor Carpi Radialis arises from the inner condyle and from 
the intermuscular fascia. Its tendon passes through a groove formed by 
the scaphoid bone and trapezium, to be inserted into the base of the meta- 
carpal bone of the index finger. 

Relations. — By its anterior surface with the fascia of the fore-arm, and 
at the wrist with the tendinous canal through which its tendon passes. 
By its posterior surface with the flexor, sublimis digitorum, flexor longus 
pollicis, wrist-joint, and groove in the scaphoid and trapezium bones. By 
its outer border with the pronator radii teres, and radial artery and veins. 
By its inner border with, the palmaris longus. The tendon is surrounded 
by a synovial membrane where it plays through the tendinous canal of the 
wrist. 

The Palmaris Longus is a small muscle which arises from the inner 
condyle, and from the intermuscular fascia. It is inserted into the annular 
ligament and palmar fascia. Occasionally this muscle is wanting. 

Relations. — By its anterior surface with the fascia of the fore-arm. By 
the posterior surface with the flexor sublimis digitorum: to the external 
side by. the flexor carpi radialis ; and to the internal side by the flexor carpi 
ulnaris. 

Cut the flexor carpi radialis and palmaris longus from their origins, in 
order to obtain a good view of the w r hole extent - of origin of the flexor 
sublimis digitorum. 

The Flexor Sublimis Digitorum (perforatus) arises from the inner 
condyle, internal lateral ligament, coronoid process of the ulna, and ob- 
lique line of the radius. The median nerve and ulnar artery pass between 
its origins. It divides into four tendons, which pass beneath the annular 
ligament into the palm of the hand, and are inserted into the base of the 
second phalanges of the fingers, splitting at their terminations to give 
passage to the tendons of the deep flexors ; thence its designation, per- 
forates. In the thecce of the fingers several small tendinous fasciculi are 
generally found, which pass between the phalanges and the edges of the 
tendons ; these have been termed the vincula accessoria. 

Relations. — In the fore-arm. By its anterior surface with the pronator 
radii teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and 
the deep fascia. By its posterior surface with the flexor profundus digi- 
torum, flexor longus pollicis, ulnar artery, veins and nerve, and median 
nerve. This muscle frequently sends a fasciculus to the flexor longus 
pollicis or flexor profundus. In the hand : its tendons, after passing be- 

maris longus. 7 One of the fasciculi of the flexor sublimis digitorum ; the rest of the 
muscle is seen beneath the tendons of the palmaris longus and flexor carpi radialis 8 
The flexor carpi ulnaris. 9. The palmar fascia. 10. The palmaris brevis muscle It. 
The abductor pollicis muscle. 12. One portion of the flexor brevis pollicis; the leading 
line crosses a part of the adductor pollicis. 13. The supinator longus muscle. 14 The 
extensor ossis metacarpi, and extensor primi internodii pollicis, curving around the lower 
border of the fore-arm. 



FLEXOR LONGUS POLLICIS. 233 

neath the annular ligament, are in relation superficially with the superficial 
palmar arch, and palmar fascia ; and deeply with the tendons of the deep 
flexor and lumbricales. 

The Flexor Carpi Ulnaris arises by two heads, one from the inner 
condyle, the other from the olecranon and upper two-thirds of the inner 
border of the ulna. Its tendon is inserted into the pisiform bone, and base 
of the metacarpal bone of the little finger. 

Relations. — By its anterior surface with the fascia of the fore-arm, with 
which it is closely united superiorly. By its posterior surface with the 
flexor sublimis digitorum, flexor profundus, pronator quadratus, and ulnar 
artery, veins, and nerve. By its radial border with the palmaris longus, 
and in the lower third of the fore-arm with the ulnar vessels and nerve. 
The ulnar nerve, and the posterior ulnar recurrent artery, pass between 
its two heads of origin. 

Deep layer. 
Flexor profundus digitorum, 
Flexor longus pollicis, 
Pronator quadratus. 

Dissection. — This group is brought into view by removing the flexor 
sublimis, and drawing aside the pronator radii teres. 

The Flexor Profundus Digitorum (perforans) arises from the upper 
two-thirds of the ulna and part of the interosseous membrane, and termi- 
nates in four tendons, which pass beneath the annular ligament, and be- 
tween the two slips of the tendons of the flexor sublimis (hence its desig- 
nation, perforans), to be inserted into the base of the last phalanges. The 
tendon of the index finger is always distinct from the rest, the other three 
tendons being more or less intimately connected by the cellular tissue and 
tendinous slips. 

Four little muscular fasciculi, called lumbricales, are connected with 
the tendons of this muscle in the palm. They will be described with the 
muscles of the hand. 

Relations. —In the fore-arm, By its anterior surface with the flexor 
sublimis digitorum, flexor carpi ulnaris, median nerve, and ulnar artery, 
veinSj and nerve. By its posterior surface with the ulna, the interosseous 
membrane, the pronator quadratus, and the wrist joint. By its radial 
border with the flexor longus pollicis, the anterior interosseous artery and 
nerve being interposed. By its ulnar border with the flexor carpi ulnaris. 
In the hand : its tendons are in relation superficially with the tendons of 
the superficial flexor ; and deeply with the interossei muscles, adductor 
pollicis, and deep palmar arch. In the fingers : the tendons of the deep 
flexor are interposed between the tendons of the superficial flexor and the 
phalanges, and give attachment to vincula accessoria. 

The Flexor Longus Pollicis arises from the upper two-thirds of the 
radius, and part of the interosseous membrane. Its tendon passes beneath 
the annular ligament, to be inserted into the base of the last phalanx of 
the thumb. 

Relations. — By its anterior surface with the flexor sublimis digitorum, 
flexor carpi radialis, supinator longus, and radial artery and veins. By 
its posterior surface with the radius, interosseous membrane, pronator 
quadratus, and wrist joint. By its ulnar border it is separated from the 
flexor profundus digitorum by the anterior interosseous artery and nerve 
20* 



234 



POSTERIOR BRACHIAL REGION. 



Fig. 123.* 



In the hand : after passing beneath the annular ligament, it is lodged in 
the interspace between the two portions of the flexor brevis pollicis, and 
afterwards in the tendinous theca of the phalanges. 

If the tendons of the last two muscles be drawn aside or divided, the 
third muscle of this group will be brought into view, lying across the 
lower part of the two bones. 

The Pronator Quadratus arises from the ulna, and is inserted into the 
lower fourth of the oblique line, on the outer side of the radius. This 
muscle occupies about the lower fourth of the two bones, is broad at its 
origin, and narrower at its insertion. 

Relations. — By its anterior surface with the ten- 
dons of the supinator longus, flexor carpi radialis, 
flexor longus pollicis, flexor profundus digitorum, 
and flexor carpi ulnaris, radial artery and veins, and 
ulnar artery, veins, and nerve. By its posterior sur- 
face w r ith the radius, ulna, and interosseous mem- 
brane. 

Actions. — The pronator radii teres and pronator 
quadratus muscles rotate the radius upon the ulna, 
and render the hand prone. The remaining muscles 
are flexors : two flexors of the wrist, flexor carpi ra- 
dialis and ulnaris ; two of the fingers, flexor sublimis 
and profundus, the former flexing the second pha- 
langes, the latter the last ; one flexor of the last pha- 
lanx of the thumb, flexor longus pollicis. The 
palmaris longus is primarily a tensor of the palmar 
fascia, and secondarily a flexor of the wrist and fore- 
arm. 

Posterior Brachial Region. 
Superficial layer. 
Supinator longus, 
Extensor carpi radialis longior, 
Extensor carpi radialis brevior, 
Extensor communis digitorum, 
Extensor minimi digiti, 
Extensor carpi ulnaris, 
Anconeus. 
Dissection. — The integument is to be divided and 
turned aside, and the fasciae removed in the same 
manner as for the anterior brachial region. 

The Supinator Longus muscle is placed along the radial border of the 
fore-arm. It arises from the external condyloid ridge of the humerus, 
nearly as high as the insertion of the deltoid, and is inserted into the base 
of the styloid process of the radius. 

Relations. — By its superficial surface with the extensor ossis metacarpi 
pollicis, extensor primi internodii pollicis, and fascia of the fore-arm. By 

*The deep layer of muscles of the fore-arm. 1. The internal lateral ligament of the 
elbow joint. 2. The anterior ligament. 3. The orbicular ligament of the head of the 
radius. 4. The flexor profundus digitorum muscle. 5. The flexor longus pollicis. '». 
The pronator quadratus. 7. The adductor pollicis muscle. 8. The dorsal interosseous 
muscle of the middle finger, and palmar interosseous of the ring finger. 9. The dorsal 
interosseous muscle of the ring finger, and palmar interosseous of the little finger. 




EXTENSOR COMMUNIS DIGITORUM. 



235 



Fig. 124* 



its deep surface with the brachialis anticus, extensor carpi radialis longior, 
tendon of the biceps, supinator brevis, pronator radii teres, flexor carpi 
radialis, flexor subJimis digitorum, flexor longus pollicis, pronator quad- 
ratic, radius, musculo-spiral nerve, radial and posterior interosseous nerve, 
and radial artery and veins. 

This muscle must be divided through the middle, and the two ends 
turned to either side to expose the next muscle. 

The Extensor Carpi Radialis Longior arises 
from the external condyloid ridge below the pre- 
ceding, and from the intermuscular fascia. Its ten- 
don passes through a groove in the radius, imme- 
diately behind the styloid process, to be inserted 
into the base of the metacarpal bone of the index 
finger. 

Relations. — By its superficial surface, with the 
supinator longus, extensor ossis metacarpi pollicis, 
extensor primi internodii pollicis, extensor secundi 
internodii pollicis, radial nerve, fascia of the fore- 
arm, and posterior annular ligament. By its deep 
surface, with the brachialis anticus, extensor carpi 
radialis brevior, radius and wrist joint. 

The Extensor Carpi Radialis Brevior is seen 
by drawing aside the former muscle. It arises from 
the external condyle of the humerus and intermus- 
cular fascia, and is inserted into the base of the me- 
tacarpal bone of the middle finger. Its tendon is 
lodged in the same groove, on the radius, with the 
extensor carpi radialis longior. 

Relations. — By its superficial surface, with the 
extensor carpi radialis longior, extensor ossis meta- 
carpi pollicis, extensor primi internodii pollicis, ex- 
tensor secundi internodii pollicis, fascia of the fore- 
arm, and posterior annular ligament. By its deep 
surface, with the supinator brevis, tendon of the 
pronator radii teres, radius and wrist joint. By its 
ulnar border, with the extensor communis digitorum. 

The Extensor Communis Digitorum arises from the external condyle, 
and intermuscular fascia; and divides into four tendons, which are inserted 
into the second and third phalanges of the fingers. At the metacarpo- 
phalangeal articulation, each tendon becomes narrow and thick, and sends 
a thin fasciculus upon each side of the joint. It then spreads out, and 
receiving the tendon of the lumbricalis, and some tendinous fasciculi from 

* The superficial layer of muscles of the posterior aspect of the fore-arm. 1. The 
lower part of the biceps. 2. Part of the brachialis anticus. 3. The lower part of the 
triceps, inserted into the olecranon. 4. The supinator longus. 5. The extensor carpi 
radialis longior. 6. The extensor carpi radialis brevior. 7. The tendons of insertion 
of these two muscles. 8. The extensor communis digitorum. 9. The extensor minimi 
digiti. 10. The extensor carpi ulnaris. 11. The anconeus. 12. Part of the flexor carp: 
ulnaris. 13. The extensor ossis metacarpi and extensor primi internodii muscle, lying 
together. 14. The extensor secundi internodii; its tendon is seen crossing the two ten- 
dons of the extensor carpi radialis longior and brevior. 15. The posterior annular liga- 
ment. The tendons of the common extensor are seen upon the back of the hand, and 
their mode of distribution on the dorsum of the fingers. 




236 ANCONEUS. 

the interossei, forms a broad aponeurosis, which covers the whole of the 
posterior aspect of the finger. At the first phalangeal joint, the aponeu- 
osis divides into three slips. The middle slip is inserted into the base 
vf the second phalanx, and the two lateral portions are continued onwards 
on each side of the joint, to be inserted into the last. Little oblique ten- 
dinous slips connect the tendons of the middle, ring, and little finger, as 
they cross the back of the hand. 

Relations. — By its superficial surface, with the fascia of the fore-arm 
and back of the hand, and with the posterior annular ligament. By its 
deep surface, with the supinator brevis, extensor ossis metacarpi pollicis, 
extensor primi internodii, extensor secundi internodii, extensor indicis, 
posterior interosseous artery and nerve, wrist joint, metacarpal bones and 
interossei muscles, and phalanges. By its radial border, with the extensor 
carpi radialis longior and brevior. By the ulnar border, with the extensor 
minimi digiti, and extensor carpi ulnaris. 

The Extensor Minimi Digiti (auricularis) is an offset from the extensor 
communis, with which it is connected by means of a tendinous slip. 
Passing down to the inferior extremity of the ulna, it traverses a distinct 
fibrous sheath, and at the metacarpophalangeal articulation unites with 
the tendon derived from the common extensor. The common tendon 
then spreads out into a broad expansion, which divides into three slips, 
to be inserted, as in the other fingers, into the last two phalanges. It is 
to this muscle that the little finger owes its power of separate extension ; 
and from being called into action when the point of the finger is intro- 
duced into the meatus of the ear, for the purpose of removing unpleasant 
sensations or producing titillation, the muscle was called by the old 
writers "auricularis." 

The Extensor Carpi Ulnaris arises from the external condyle and 
from the upper two-thirds of the border of the ulna. Its tendon passes 
through the posterior groove, in the lower extremity of the ulna, to be 
inserted into the base of the metacarpal bone of the little finger. 

Relations. — By its superficial surface, with the fascia of the fore-arm, 
and posterior annular ligament. By its deep surface, with the supinator 
brevis, extensor ossis metacarpi pollicis, extensor secundi internodii, ex- 
tensor indicis, ulna, and wrist joint. By its radial border, it is in relation 
with the extensor communis digitorum, and extensor minimi digiti : and 
by the ulnar border, with the anconeus. 

The Anconeus is a small triangular muscle, having the appearance of 
being a continuation of the triceps ; it arises from the outer condyle, and 
is inserted into the olecranon and triangular surface on the upper extremity 
of the ulna. 

Relations. — By its superficial surface with a strong tendinous aponeu- 
rosis derived from the triceps. By its deep surface with the elbow joint, 
orbicular ligament, and slightly with the supinator brevis. 

Deep Layer. 

Supinator brevis, 
Extensor ossis metacarpi pollicis, 
Extensor primi internodii pollicis, 
Extensor secundi internodii pollicis, 
Extensor indicis. 



EXTENSOR PRIMI INTERNODII POLLICIS. 



237 



Dissection. — The muscles of the superficial layer Fig 125.» 

should be removed in order to bring the deep group 
completely into view. 

The Supinator Brevis cannot be seen in its en- 
tire extent until the radial extensors of the carpus 
are divided from their origin. It arises from the 
external condyle, from the external lateral and or- 
bicular ligament, and from the ulna, and winds 
around the upper part of the radius, to be inserted 
into the upper third of its oblique line. The pos- 
terior interosseous artery and nerve are seen perfo- 
rating the lower border of this muscle. 

Relations. — By its superficial surface with the 
pronator radii teres, supinator longus, extensor 
carpi radialis longior and brevior, extensor com- 
munis digitorum, extensor carpi ulnaris, anconeus, 
the radial artery and veins, the. musculo-spiral 
nerve, radial and posterior interosseous nerve. 
By its deep surface with the elbow-joint and its 
ligaments, the interosseous membrane, and the 
radius. 

The Extensor Oss§s Metacarpi Pollicis is 
placed immediately below the supinator brevis. 
It arises from the ulna, interosseous membrane, and 
radius, and is inserted, as its name implies, into the 
base of the metacarpal bone of the thumb. Its 
tendon passes through the groove immediately in 
front of the styloid process of the radius. 

Relations. — By its superficial surface with the extensor caijpi ulnaris, 
extensor minimi digiti, extensor communis digitorum, fascia of the fore- 
arm, and annular ligament. By its deep surface with the ulna, interosse- 
ous membrane, radius, tendons of the extensor carpi radialis longior and 
brevior, and supinator longus, and at the wrist with the radial artery. 
By its upper border with the edge of the supinator brevis. By its lower 
border with the extensor secundi and primi internodii. The muscle is 
crossed by branches of the posterior interosseous artery and nerve. 

The Extensor Primi Internodii Pollicis, the smallest of the muscles 
in this layer, arises from the interosseous membrane and ulna, and passes 
through the same groove with the extensor ossis metacarpi, to be inserted 
into the base of the first phalanx of the thumb. 

Relations. — The same as those of the preceding muscle with the excep- 
tion of the extensor carpi ulnaris. The muscle accompanies the extensor 
ossis metacarpi. 

The Extensor Secundi Internodii Pollicis arises from the ulna, and 
interosseous membrane. Its tendon passes through a distinct canal in the 
annular ligament, and is inserted into the base of the last phalanx of the 
thumb. 

* The deep layer of muscles on the posterior aspect of the fore-arm. 1. The lower 
part of the humerus. 2. The olecranon. 3. The ulna. 4. The anconeus muscle. 5. 
The supinator brevis muscle. 6. The extensor ossis metacarpi pollicis. 7. The exten- 
sor primi internodii pollicis. 8. The extensor secundi internodii pollicis. 9. The ex- 
tensor indicis. 10. The first dorsal interosseous muscle. The other three dorsal inter- 
ossei are seen between the metacarpal bones of their respective fingers. 




238 MUSCLES OF THE HAND. 

Relations. — By its external surface with the same relations as the exten- 
sor ossis metacarpi. By its deep su?face with the ulna, interosseous mem- 
brane, radius, wrist joint, radial artery, and metacarpal bone of the thumb. 
The muscle is placed between the extensor primi internodii and extensor 
indicis. s 

The Extensor Indicis arises from the ulna, as high up as the extensor 
ossis metacarpi pollicis, and from the interosseous membrane. Its tendon 
passes through a distinct groove in the radius, and is inserted into the 
aponeurosis formed by the common extensor tendon of the index finger. 

Relations. — The same as those of the preceding muscle, with the ex- 
ception of the hand, where the tendon rests upon the metacarpal bone of 
the fore finger and second interosseous muscle, and has no relation with 
the radial artery. 

The tendons of the extensors, as of the flexor muscles of the fore-arm, 
are provided with synovial bursse as they pass beneath the annular liga- 
ments : those of the back of the wrist have distinct sheaths, formed by the 
posterior annular ligament. 

Actions. — The anconeus is associated in its action with the triceps ex- 
tensor cubiti : it assists in extending the fore-arm upon the arm. The 
supinator longus and brevis effect the supination of the fore-arm, and an- 
tagonize the two pronators. The extensor carpi radialis longior and bre- 
vior, and ulnaris, extend the wrist in opposition gto the two flexors of the 
carpus. The extensor communis digitorum restores the fingers to the 
straight position, after being flexed by the two flexors, sublimis and pro- 
fundus. The extensor ossis metacarpi, primi internodii, and secundi in- 
ternodii pollicis, are the especial extensors of the thumb, and serve to 
balance the actions of the flexor ossis metacarpi, flexor brevis, and flexor 
longus pollicis. The extensor indicis gives the character of extension to 
the index finger, and is hence named " indicator," and the extensor 
minimi digiti supplies that finger with the power of exercising a distinct 
extension. 

MUSCLES OF THE HAND. 

Radial or Thenar Region. 
Abductor pollicis, Flexor brevis pollicis, 

Flexor ossis metacarpi (opponens), Adductor pollicis. 

Dissection. — The hand is best dissected by making an incision along 
the middle of the palm, from the wrist to the base of the fingers, and 
crossing it at each extremity by a transverse incision, then turning aside 
the flaps of integument. For exposing the muscles of the radial region, 
the removal of the integument and fascia on the radial side will be suffi- 
cient. 

The Abductor Pollicis is a small, thin muscle, which arises from the 
scaphoid bone and annular ligament. It is inserted into the base of the 
first phalanx of the thumb. 

Relations. — By its superficial surface, with the external portion of the 
palmar fascia. By its deep surface, with the flexor ossis metacarpi. On 
its inner side it is separated by a narrow cellular interspace from the flexor 
brevis pollicis. 

This muscle must be divided from its origin and turned upwards, in 
order to see the next. 



MUSCLES OF THE HAND. 



239 



Fig. 126 * 




The Flexor Ossis Metacarpi (oppo- 
nens pollicis) arises from the trapezium 
and annular ligament, and is inserted 
into the whole length of the metacarpal 
bone. 

Relations. — By its superficial surface, 
with the abductor pollicis. By its deep 
surface, with the trapezio-metacarpal ar- 
ticulation, and with the metacarpal bone. 
Internally, with the flexor brevis pollicis. 

The flexor ossis metacarpi may now 
be divided from its origin and turned 
aside, in order to show the next muscle. 

The Flexor Brevis Pollicis consists 
of two portions, between which lies the 
tendon of the flexor longus pollicis. The 
external portion arises from the trapezium 
and annular ligament ; the internal por- 
tion, from the trapezoides and os mag- 
num. They are both inserted into the 
base of the first phalanx of the thumb, having a sesamoid bone in each of 
their tendons, to protect the joint. 

Relations. — By its superficial surface, with the external portion of the 
palmar fascia. By its deep surface, with the adductor pollicis, tendon of 
the flexor carpi radialis, and trapezio-metacarpal articulation. By its ex- 
ternal surface, with the flexor ossis metacarpi and metacarpal bone. By 
its inner surface, with the tendons of the long flexor muscles and first 
4 lumbricalis. 

The Adductor Pollicis is a triangular muscle ; it arises from the whole 
length of the metacarpal bone of the middle finger ; and the fibres converge 
to its insertion into the base of the first phalanx. 

Relations. — By its anterior surface with the flexor brevis pollicis, ten- 
dons of the deep flexor of the fingers, lumbricales, and deep palmar arch. 
By its posterior surface with the metacarpal bones of the index and middle 
fingers, the interossei of the second interosseous space, and the abductor 
indicis. Its inferior border is subcutaneous. 

Ulnar, or Hypothenar Region. 
Palmaris brevis, 
Abductor minimi digiti, 
Flexor brevis minimi digiti, 
Flexor ossis metacarpi (adductor). 

*The muscles of the hand. 1. The' annular ligament. 2, 2. The origin and insertion 
of the abductor pollicis muscle; the middle portion has been removed. 3. The flexor 
ossis metacarpi, or opponens pollicis. 4. One portion of the flexor brevis pollicis. 5. 
The deep portion of the flexor brevis pollicis. 6. The adductor pollicis. 7. 7. The 
lumbricales muscles, arising from the deep flexor tendons, upon which the numbers are 
placed. The tendons of the flexor sublimis have been removed from the palm of the 
hand. 8. One of the tendons of the deep flexor, passing between the two terminal slips 
of the tendon of the flexor sublimis, to reach the last phalanx. 9. The tendon of the 
flexor longus pollicis, passing between the two portions of the flexor brevis to the last 
phalanx. 10. The abductor minimi digiti. 11. The flexor brevis minimi digiti. The 
edge of the flexor ossis metacarpi, or adductor minimi digiti, is seen projecting beyond 
the inner border of the flexor brevis. 12. The prominence of the pisiform bone. 13. 
The first dorsal interosseous muscle. 



240 MUSCLES OF THE HAND. 

Dissection. — Turn aside the ulnar flap of integument in the palm of the. 
hand : in doing this, a subcutaneous muscle, the palmaris brevis will be 
exposed. After examining this muscle remove it with the deep fascia, in 
order to bring into view the muscles of the little finger. • 

The Palmaris Brevis is a thin plane of muscular fibres which arises 
from the annular ligament and palmar fascia, and passes transversely in- 
wards, to be inserted into the integument on the inner border of the hand. 

Relations. — By its superficial surface with the fat and integument of the 
ball of the little finger. By its deep surface with the internal portion of the 
palmar fascia, which separates it from the ulnar artery veins, and nerve, 
and from the muscles of the inner border of the hand. 

The Abductor Minimi Digiti is a small tapering muscle which arises 
from the pisiform bone, and is inserted into the base of the first phalanx of 
the little finger. 

Relations. — By its superficial surface with the internal portion of the 
deep fascia and the palmaris brevis : by its deep surface with the flexor 
ossis metacarpi and metacarpal bone. By its inner border with the flexor 
brevis minimi digiti. 

The Flexor Brevis Minimi Digiti is a small muscle arising from the 
unciform bone and annular ligament, and inserted into the base of the first 
phalanx. It is sometimes wanting. 

Relations. — By its superficial surface with the internal portion of the 
palmar fascia, and the palmaris brevis. By its deep surface with the flexor 
ossis metacarpi, and metacarpal bone. Externally with the abductor 
minimi digiti, from which it is separated near its origin by the deep palmar 
branch of the ulnar nerve and communicating artery. Internally with the 
tendons of the flexor sublimis and profundus. 

The Flexor Ossis Metacarpi (adductor, opponens) arises from the 
unciform bone and annular ligament, and is inserted into the whole length 
of the metacarpal bone of the little finger. 

Relations. — By its superficial surface with the flexor brevis and abductor 
minimi digiti. By its deep surface with the interossei muscles of the last 
metacarpal space, the metacarpal bone, and the flexor tendons of the little 
finger. 

Palmar Region. 
Lumbricales, 
Interossei palmares, 
Interossei dorsales. 

The Lumbricales, four in number, are accessories to the deep flexor 
muscle. They arise from the tendons of the deep flexor ; the first and 
second from the palmar side, the third from the ulnar, and the fourth from 
the radial side ; and are inserted into the aponeurotic expansion of the 
extensor tendons on the radial side of the fingers. The third, or that of 
the tendon of the ring finger, sometimes bifurcates, otherwise it is inserted 
wholly into the extensor tendon of the middle finger. 

Relations. —In the palm of the hand w T ith the flexor tendons ; at their 
insertion, with the tendons of the interossei and the metacarpo-phalangeal 
articulations. 

The Palmar Interossei, three in number, are placed upon the meta- 
carpal bones, rather than between them. They arise from the base of the 
metacarpal bone of one finger, and are inserted into the base of the first 



MUSCLES OF THE HAND. 



241 



Fig. 127.* 



Fig. 128.f 





phalanx and aponeurotic expansion of tne extensor tendon of the same 
finger. The first belongs to the index finger; the second to the ring 
finger; and the third to the little finger; the middle finger being ex- 
cluded. 

Relations. — By their palmar surface with the flexor tendons and with 
the deep muscles in the palm of the hand. By their dorsal surface with 
the dorsal interossei. On one side with the metacarpal bone, on the other 
with the corresponding dorsal interosseous. 

Dorsal Interossei. — On turning to the dorsum of the hand, the four 
dorsal interossei are seen in the four spaces between the metacarpal bones. 
They are bipenniform muscles and arise by two heads, from the adjoining 
sides of the base of the metacarpal bones. They are inserted into the base 
of the first phalanges, and aponeurosis of the extensor tendons. 

The first is inserted into the index finger, and from its use is called 
abductor indicis,J the second and third are inserted into the middle finger 
compensating its exclusion from the palmar group ; the fourth is attached 
to the ring finger ; so that each finger is provided with two interossei, 
with the exception of the little finger, as may be shown by means of a 
table, thus : — 

T 7 n { one dorsal (abductor indicis), 

Index finger, < -, v n 

J 6 ' I one palmar. 

Middle finger, two dorsal. 
„. r. { one palmar, 

&J b > £ one dorsal. 
Little finger, remaining palmar. 

Relations. — By their dorsal surface with a thin aponeurosis which sepa- 
rates them from the tendons on the dorsum of the hand. By their palmar 

* Palmar interossei. 1. Adductor indicis. 2. Abductor annularis. 3. Interosseous 
auricularis. 

■j- Dorsal interossei. 1. Abductor indicis. 2. Abductor medii. 3. Adductor medii. 
4. Adductor annularis. 

t Horner divides this muscle and calls one portion of it abductor indicis and the other 
prior indicis. Wilson's description is the best, as it makes the analogy between the foot 
and hand complete, whilst there is a great discrepancy in Horner's mode of describing 
them. — G. 

21 Q 



242 



MUSCLES OF THE LOWER EXTREMITY. 



surface with the muscles and tendons in the palm of the hand. By one 
side with the metacarpal bone ; by the other with the corresponding palmar 
interosseous. The abductor indicis is in relation by its palmar surface 
with the adductor pollicis, the arteria magna pollicis being interposed. 
The radial artery passes into the palm of the hand between the two heads 
of the first dorsal interosseous muscle and the perforating branches of the 
deep palmar arch, between the heads of the other dorsal interossei. 

Actions. — The actions of the muscles of the hand are expressed in their 
names. Those of the radial region belong to the thumb, and provide for 
three of its movements, abduction, adduction, and flexion. The ulnar 
group, in like manner, are subservient to the same motions of the little 
finger, and the interossei are abductors and adductors of the several fin- 
gers. The lumbricales are accessory in their actions to the deep flexors : 
they were called by the earlier anatomists, fldicinii, i. e. fiddlers' muscles, 
from an idea that they might effect the fractional movements by which the 
performer is enabled to produce the various notes on that instrument. 

In relation to the axis of the hand, the four dorsal interossei are abduc- 
tors, and the three palmar, adductors. It wil) therefore be seen that each 
finger is provided with its proper adductor and abductor, two flexors., and 
(with the exception of the middle and ring fingers) two extensors. The 
thumb has moreover a flexor and extensor of the metacarpal bone ; and 
the little finger a flexor of the metacarpal bone without an extensor. 

MUSCLES OF THE LOWER EXTREMITY. 



The muscles of the lower extremity may be arranged into groups cor- 
responding with the regions of the hip, thigh, leg, and foot, as in the fol- 



lowing table 



Gluteus maximus, 
Gluteus minimus, 
Gemellus superior, 
Gemellus inferior, 
Quadratus femoris. 



HIP. 

Gluteal Region. 

Gluteus medius, 
Pyriformis, 
Obturator internus, 
Obturator externus. 



THIGH. 

Anterior Femoral Region. Internal Femoral Region. 

Tensor vaginae femoris, Iliacus internus, 



Sartorius, 
Rectus, 

Vastus internus, 
Vastus externus. 
Crureus. 



Psoas magnus, 
Pectineus, 
Adductor longus, 
Adductor brevis, 
Adductor magnus, 
Gracilis. 



Posterior Femoral Region. 

Biceps, 

Semitendinosus, 

Semimembranosus. 



MUSCLES OF THE LOWER EXTREMITY, ETC. 



243 



LEG. 



interior Tibial Region. 

Tibialis anticus, 
Extensor longus digitorum, 
Peroneus tertius, 
Extensor longus pollicis. 

Fibular Region. 

Peroneus longus, 
Peroneus brevis. 



Posterior Tibial Region. 
Superficial Group. 
Gastrocnemius, 
Plantaris, 
Soleus. 

Deep [posterior] Layer. 

Popliteus, 

Flexor longus pollicis, 
Flexor longus digitorum, 
Tibialis posticus. 



FOOT. 

Dorsal Region. 

Extensor brevis digitorum, 
Interossei dorsales. 



1st Layer. 

Abductor pollicis, 
Abductor minimi digiti, 
Flexor brevis digitorum. 

2d Layer. 
Musculus accessorius, 
Lumbricales. 



Plantar Region. 

3d Layer. 

Flexor brevis pollicis, 
Adductor pollicis, 
Flexor brevis minimi digiti, 
Transversus pedis. 

4:th Layer. 
Interossei plantares. 



GLUTEAL REGION 



Obturator internus, 
Gemellus inferior. 
Obturator externus, 
Quadratus femoris. 



Gluteus maximus, 
Gluteus medius, 
Gluteus minimus, 
Pyriformis, 
Gemellus superior, 

Dissection. — The subject being turned on its face, and a block placed 
beneath the os pubis to support the pelvis, the student commences the 
dissection of this region, by carrying an incision from the apex of the 
coccyx along the crest of the ilium to its anterior superior spinous process ; 
or vice versa, if he be on the left side. He then makes an incision from 
the posterior fifth of the crest of the ilium, to the apex of the trochanter, 
major, this marks the upper border of the gluteus maximus ; and a third 
incision from the apex of the coccyx along the fleshy margin of the lower 
border of the gluteus maximus, to the outer side of the thigh, about four 
inches below the apex of the trochanter major. He then reflects the inte- 
gument, superficial fascia, and deep fascia, which latter is very thin over 
this muscle, from the gluteus maximus, following rigidly the course of its 
fibres ; and having exposed the muscle in its entire extent, he dissects the 
integument and superficial fascia from off the deep fascia which binds 
down the gluteus medius, the other portion of this region. 



244 



MUSCLES OF THE GLUTEAL REGION. 




Fig. 129 * The Gluteus Maximus (7X0UT0S, nates) 

is the thick, fleshy mass of muscle, of a 
quadrangular shape, which forms the con- 
vexity of the nates. In structure, it is ex- 
tremely coarse, being made up of large 
fibres, which are collected into fasciculi, 
and these again into distinct muscular 
masses, separated by deep cellular fur- 
rows. It arises from the posterior fifth of 
the crest of the ilium, from the posterior 
surface of the sacrum and coccyx, and 
from the great sacro-ischiatic ligament. It 
passes obliquely outwards and downwards, 
to be inserted into the rough line leading 
from the trochanter major to the linea 
aspera, and is continuous by means of its 
tendon with the fascia lata covering the 
outer side of the thigh. A large bursa is 
situated between the broad tendon of this 
muscle and the femur. 
Relations. — By its superficial surface with a thin aponeurotic fascia, 
which separates it from the superficial fascia and integument, and with 
the vastus externus, a bursa being interposed. By its deep surface with 
the gluteus medius, pyriformis, gemelli, obturator internus, quadratus 
femoris, sacro-ischiatic foramina, great sacro-ischiatic ligament, tuberosity 
of the ischium, semimembranosus, semitendinosus, biceps, and adductor 
magnus ; the gluteal vessels and nerves, ischiatic vessels and nerves, and 
internal pudic vessels and nerve. By its upper border it overlaps the 
gluteus medius ; and by the lower border forms the lower margin of the 
nates. 

The gluteus maximus must be turned down from its origin, in order to 
bring the next muscle into view. 

The Gluteus Medius is placed in front of, rather than beneath the 
gluteus maximus ; and is covered in by a process of the deep fascia, 
which is very thick and dense. It arises from the outer lip of the crest 
of the ilium for four-fifths of its length, from the surface of bone between 
that border and the superior curved line on the dorsum ilii, and from the 
dense fascia above-mentioned. Its fibres converge to the outer part of 
the trochanter major, into which its tendon is inserted. 

Relations. — By its superficial surj ace with the tensor vaginae femoris, 
gluteus maximus, and its fascia. By its deep surface with the gluteus 
minimus, and gluteal vessels and nerves. By its lower border with the 
pyriformis muscle. A bursa is interposed between its tendon and the 
upper part of the trochanter major. 

* The deep muscles of the gluteal region. 1. The external surface of the ilium. 2. 
The posterior surface of the sacrum. 3. The posterior sacro-iliac ligaments. 4. The 
tuberosity of the ischium. 5. The great or posterior sacro-ischiatic ligament. 6. The 
lesser or anterior sacro-ischiatic ligament. 7. The trochanter major. 8. The gluteus 
minimus. 9. The pyriformis. 10. The gemellus superior. 1 1. The obturator internus 
muscle, passing out of the lesser sacro-ischiatic foramen. 12. The gemellus inferior. 
13. The quadratus femoris. 14, The upper part of the adductor magnus. 15. The 
vastus externus. 10. The biceps. 17. The gracilis. 18. The semitendinosus. 



OBTURATOR INTERNUS. 245 

This muscle should now be removed from its origin and turned down, 
so as to expose the next, which is situated beneath it. 

The Gluteus Minimus is a radiated muscle, arising from the surface 
of the dorsum ilii, between the superior and inferior curved lines ; its 
fibres converge to the anterior border of the trochanter major, into which 
it is inserted by means of a rounded tendon. There is no distinct line of 
separation between the gluteus medius and minimus anteriorly. 

Relations. — By its superficial surface with the gluteus medius, and 
gluteal vessels. By its deep surface with the surface of the ilium, the 
long tendon of the rectus femoris, and the capsule of the hip joint. A 
bursa is interposed between the tendon of the muscle and the trochanter. 

The Pyriformis muscle (pyrum, a pear, i. e. pear-shaped) arises from 
the anterior surface of the sacrum, by little slips that are interposed be- 
tween the first and fourth anterior sacral foramina, and from the adjoining 
surface of the ilium. It passes out of the pelvis, through the great sacro- 
ischiatic foramen, and is inserted by a rounded tendon into the trochanteric 
fossa of the femur. 

Relations. — By its superficial or external surface with the sacrum and 
gluteus maximus. By its deep or pelvic surface with the rectum, the 
sacral plexus of nerves, the branches of the internal iliac artery, the great 
sacro-ischiatic notch, and the capsule of the hip joint. By its upper border 
with the gluteus medius and gluteal vessels and nerves. By its lower 
border with the gemellus superior, ischiatic vessels and nerves, and internal 
pudic vessels and nerve. 

The Gemellus Superior (gemellus, double, twin) is a small slip of 
muscle, situated immediately below the pyriformis ; it arises from the 
spine of the ischium, and is inserted into the upper border of the tendon 
of the obturator internus, and into the trochanteric fossa of the femur. 
The gemellus superior is not unfrequently wanting. 

Relations. — By its superficial surface with the gluteus maximus, the 
ischiatic vessels and nerves, and internal pudic vessels and nerve. By its 
deep surface with the pelvis, and capsule of the hip joint. 

The Obturator Internus arises from the inner surface of the anterior 
wall of the pelvis, being attached to the margin of bone around the obtu- 
rator foramen, and to the obturator membrane. It passes out of the pelvis 
through the lesser sacro-ischiatic foramen, and is inserted by a flattened 
tendon into the trochanteric fossa of the femur. The lesser sacro-ischiatic 
notch, over which this muscle plays as through a pulley, is faced with 
cartilage, and provided with a synovial bursa to facilitate its movements. 
The tendon of the obturator is supported on each side by the two gemelli 
muscles (hence their names), which are inserted into the sides of the ten- 
don, and appear to be auxiliaries or superadded portions of the obturator 
internus. 

Relations. — By its superficial or posterior surface with the internal pudic 
vessels and nerve, the obturator fascia, which separates it from the levator 
ani and viscera of the pelvis, the sacro-ischiatic ligaments, gluteus maxi- 
mus, and ischiatic vessels and nerves. By its deep or anterior surface 
with the obturator membrane and the margin of bone surrounding it, the 
cartilaginous pulley of the lesser ischiatic foramen, the external surface of 
the pelvis, and the capsular ligament of the hip joint. By its upper border, 
within the pelvis, with the obturator vessels and nerve ; externally to the 
21* 



246 ANTERIOR FEMORAL REGION. 

peivis, with the gemellus superior. By its lower border with the gemellus 
inferior. 

The Gemellus Inferior aiises from the posterior point of the tuberosity 
of the ischium, and is inserted into the lower border of the tendon of the 
obturator internus, and into the trochanteric fossa of the femur. 

Relations. — By its superficial surface with the gluteus maximus, and 
ischiatic vessels and nerves. By its deep surface with the external surface 
of the pelvis, and capsule of the hip joint. By its upper border with the 
tendon of the obturator internus. By its lower border with the tendon of 
the obturator extemus and quadratus femoris. 

In this region the tendon only of the obturator extemus can be seen, 
situated deeply between the gemellus inferior and the upper border of the 
quadratus femoris. To expose this muscle fully, it is necessary to dissect 
it from the anterior part of the thigh, after the removal of the pectineus, 
adductor longus and adductor brevis muscles. 

The Obturator Externus muscle (obturare, to stop up) arises from 
the obturator membrane, and from the surface of bone immediately sur- 
rounding it anteriorly, viz. from the ramus of the os pubis and ischium : 
its tendon passes behind the neck of the femur, to be inserted with the 
external rotator muscles, into the trochanteric fossa of the femur. 

Relations. — By its superficial or anterior surface with the tendon of the 
psoas and iliacus, pectineus, adductor brevis and magnus, the obturator 
vessels and nerve. By its deep or posterior surface with the obturator 
membrane and the margin of bone which surrounds it, the lower part of 
the capsule of the hip joint and the quadratus femoris. 

The Quadratus Femoris (square-shaped) arises from the external bor- 
der of the tuberosity of the ischium, and is inserted into a rough line on 
the posterior border of the trochanter major, which is thence named linea 
quadrati. 

Relations. — By its posterior surface with the gluteus maximus, and is- 
chiatic vessels and nerves. By its anterior surface with the tendon of the 
obturator externus, and trochanter minor, a synovial bursa often separating 
it from the latter. By its upper border with the gemellus inferior ; and by 
the lower border with the adductor magnus. 

Actions. — The glutei muscles are abductors of the thigh, when they 
take their fixed point from the pelvis. Taking their fixed point from the 
thigh, they steady the pelvis on the head of the femur ; this action is pe- 
culiarly obvious in standing on one leg ; they assist also in carrying the 
leg forward, in progression. The gluteus minimus being attached to the 
anterior border of the trochanter major, rotates the limb slightly inwards. 
The gluteus medius and maximus, from their insertion into the posterior 
aspect of the bone, rotate the limb outwards ; the latter is, moreover, a 
tensor of the fascia of the thigh. The other muscles rotate the limb out- 
wards, everting the knee and foot ; hence they are named external rotators. 

Anterior Femoral Region. 

Tensor vaginas femoris, Vastus internus, 

Sartorius, Vastus externus, 

Rectus, Crureus. 

Dissection. — Make an incision along the line of Poupart's ligament, 
from the anterior superior spinous process of the ilium to the spine of the 



TENSOR VAGINAE FEMORIS — SARTORIUS. 



247 



Fig. 130.* 



os pubis ; and a second, from the middle of the preceding down the inner 
side of the thigh, and across the inner condyle of the femur, to the head 
of the tibia, where it may be bounded by a transverse incision. Turn 
back the integument from the whole of this region, and examine the super- 
ficial fascia ; which is next to be removed in the same manner. After the 
deep fascia has been well considered, it is likewise to be removed, by dis- 
secting it off in the course of the fibres of the muscles. As it might not 
be convenient to the junior student to expose so large a surface at once as 
ordered in this dissection, the vertical incision may be crossed by one or 
two transverse incisions, as may be deemed most proper. 

The Tensor Vagina Femoris (stretcher of the sheath of the thigh) is a 
short flat muscle, situated on the outer side of the hip. It arises from the 
crest of the ilium, near its anterior superior spinous process, and is inserted 
between two layers of the fascia lata at about one-fourth down the thigh. 

Relations. — By its superficial surface with the fascia 
lata and integument. By its deep surface with the in- 
ternal layer of the fascia lata, gluteus medius, rectus 
and vastus externus. By its inner border near its ori- 
gin with the sartorius. 

The Sartorius (tailor's muscle) is a long riband- 
like muscle, arising from the anterior superior spinous 
process of the ilium, and from the notch immediately 
below that process ; it crosses obliquely the upper 
third of the thigh, descends behind the inner condyle 
of the femur, and is inserted by an aponeurotic expan- 
sion into the inner tuberosity of the tibia. This ex- 
pansion covers in the insertion of the tendons of the 
gracilis and semitendinosus muscles. The inner bor- 
der of the sartorius muscle is the guide to the opera- 
tion for tying the femoral artery in the middle of its 
course. 

Relations. — By its superficial surface with the fascia 
lata and some cutaneous nerves. By its deep surface 
with the psoas and iliacus, rectus, sheath of the femo- 
ral vessels and saphenous nerves, vastus internus, ad- 
ductor longus, adductor magnus, gracilis, long saphe- 
nous nerve, internal lateral ligament of the knee joint. 
By its expanded insertion with the tendons of the gra- 
cilis and semi-tendinosus, a synovial bursa being inter- 
posed. At the knee joint its posterior border is in 
relation with the internal saphenous vein. At the up- 
per third of the thigh the sartorius forms, with the lower 
border of the adductor longus, an isosceles triangle, 
whereof the base corresponds with Poupart's ligament, 
line drawn from the middle of the base of the apex of this triangle, imme- 
diately overlies the femoral artery with its sheath. 




A perpendicular 



* The muscles of the anterior femoral region. 1. The crest of the ilium. 2. Its an- 
terior superior spinous process. 3. The gluteus medius. 4. The tensor vaginae femoris; 
its insertion into the fascia lata is shown inferiorly. 5. The sartorius. 6. The rectus. 
7. The vastus externus. 8. The vastus internus. 9. The patella. 10. The iliacus in- 
ternus. 11. The psoas magnus. 12. The pectineus. 13. The adductor longus. 14. 
Part of the adductor magnus. 15. The gracilis. 



248 VASTUS INTERNUS — CRUREUS. 

The Rectus (straight) muscle is fusiform in its shape and bipenniform 
in the disposition of its fibres. It arises by two round tendons, one from 
the anterior inferior spinous process of the ilium, the other from the upper 
lip of the acetabulum ; and is inserted by a broad and strong tendon, into 
the upper border of the patella. It is more correct to consider the patella 
as a sesamoid bone, developed within the tendon of the rectus ; and the 
ligamentum patella?, as the continuation of the tendon to its insertion into 
the tubercle of the tibia. , 

Relations. — By its superficial surface with the gluteus medius, psoas 
and iliacus, sartorius ; and, for the lower three-fourths of its extent, with 
the fascia lata. By its deep surface with the capsule of the hip joint, the 
external circumflex vessels, crureus, and vastus internus and externus. 

The rectus must now be divided through its middle, and the two ends 
turned aside, to bring clearly into view the next muscles. 

The three next muscles are generally considered collectively under the 
name of triceps extensor cruris. Adopting this view, the muscle surrounds 
the whole of the femur, excepting the rough line (linea aspera) upon its 
posterior aspect. Its division into three parts is not well defined, ; the 
fleshy mass upon each side being distinguished by the names of vastus 
internus and externus, the middle portion by that of crureus. 

The Vastus Externus, narrow below and broad above, arises from 
the outer border of the patella, and is inserted into the femur and outer 
side of the linea aspera, as high as the base of the trochanter major. 

Relations. — By its superficial surface with the fascia lata, rectus, biceps, 
semi-membranosus and gluteus maximus, a synovial bursa being inter- 
posed between it and the latter. By its deep surface with the crureus and 
femur. 

The Vastus Internus, broad below and narrow above, arises from 
the inner border of the patella, and is inserted into the femur and inner 
side of the linea aspera as high up as the anterior intertrochanteric line. 

' Relations. — By its superficial surface with the psoas and iliacus, rectus, 
sartorius, femoral artery and vein and saphenous nerves, pectineus, ad- 
ductor longus, brevis, and magnus, and fascia lata. By its deep surface 
with the crureus and femur. 

The Crureus (crus, the leg) arises from the upper border of the patella, 
and is inserted into the front aspect of the femur, as high as the anterior 
intertrochanteric line. When the crureus is divided from its insertion, a 
small muscular fasciculus is often seen upon the lower part of the femur, 
which is inserted into the pouch of synovial membrane, that extends up- 
wards from the knee joint, behind the patella. This is named, from its 
situation, sub-crureus, and would seem to be intended to support the 
synovial membrane. 

Relations. — By its superficial surface with the external circumflex 
• vessels, the rectus, vastus internus and externus. By its deep surface with 
the femur, the sub-crureus, and synovial membrane of the knee joint. 

Jictions. — The tensor vaginae femoris renders the fascia lata tense, and 
slightly inverts the limb. The sartorius flexes the leg upon the thigh, and, 
continuing to act, the thigh upon the pelvis, at the same time carrying the 
leg across that of the opposite side, into the position in which tailors sit ; 
hence its name. Taking its fixed point from below, it assists the extensor 
muscles in steadying the leg, for the support of the trunk. The other four 
muscles have been collectively named quadriceps extensor, from their 



INTERNAL FEMORAL REGION. 249 

similarity of action. They extend the leg upon the thigh, and obtain a 
oreat increase of power by their attachment to the patella, which acts as a 
fulcrum. Taking their fixed point from the tibia, they steady the femur 
upon the leg, and the rectus, by being attached to the pelvis, serves to 
balance the trunk upon the lower extremity. 

Internal Femoral Region. * 

Iliacus internus, Adductor brevis, 

Psoas magnus, Adductor magnus, 

Pectineus, Gracilis. 
Adductor longus, 

Dissection. — These muscles are exposed by the removal of the inner 
flap of integument recommended in the dissection of the anterior femora! 
region. The iliacus and psoas arising from within the abdomen, can only 
be seen in their entire extent after the removal of the viscera from that 
cavity. 

The Iliacus Internus is a flat radiated muscle. It arises from the 
whole extent of the inner concave surface of the ilium ; and, after joining 
with the tendon of the psoas, is inserted into the trochaiiter minor of the 
femur. A few fibres of this muscle are derived from the base of the sa- 
crum, and others from the capsular ligament of the hip joint. 

Relations. — By its anterior surface, within the pelvis, with the external 
cutaneous nerve, and with the iliac fascia, which separates the muscle 
from the peritoneum, on the right from the 'caecum, and on the left from 
the sigmoid flexure of the colon ; externally to the pelvis with the fascia 
lata, rectus, and sartorius. By its posterior surface with the iliac fossa, 
margin of the pelvis, and with the capsule of the hip joint, a synovial 
bursa of large size being interposed, which is sometimes continuous with 
the synovial membrane of the articulation. By its inner border with the 
psoas magnus and crural nerve. 

The Psoas Magnus (-^oa, lumbus, a loin), situated by the side of the 
vertebral column in the loins, is a long fusiform muscle. It arises from 
the intervertebral substances, part of the bodies and bases of the trans- 
verse processes, and from a series of tendinous arches, thrown across the 
constricted portion of the last dorsal and four upper lumbar vertebrae. 
These arches are intended to protect the lumbar arteries and sympathetic 
filaments of nerves from pressure, in their passage beneath the muscle. 
From this extensive origin, the muscle passes along the margin of the 
brim of the pelvis, and beneath Poupart's ligament, to its insertion. The 
tendon of the psoas magnus unites with that of the iliacus, and the con- 
joined tendon is inserted into the posterior part of the trochanter minor, a 
bursa being interposed. 

Relations. — By its anterior surface, with the ligamentum arcuatum in- 
ternum of the diaphragm, the kidney, the psoas parvus, genito-crural 
nerve, sympathetic nerve, its proper fascia, the peritoneum and colon, and 
along its pelvic border with the common and external iliac artery and 
vein. By its posterior surface, with the lumbar vertebrae, the lumbar ar- 
teries, quadratus lumborum, from which it is separated by the anterior 
layer of the aponeurosis of the transversalis, and with the crural nerve, 
which, near Poupart's ligament, gets to its outer side. The lumbar plexus 
of nerves is situated in the substance of the posterior part of the muscle. 



250 ADDUCTOR BREVIS. 

In the thigh, the muscle is in relation with the fascia lata in front ; the 
border of the pelvis and hip joint, from which it is separated by the syno- 
vial membrane, common to it and the preceding muscle, behind ; with the 
crural nerve and iliacus, to the outer side ; and with the femoral artery, 
by which it is slightly overlaid, to the inner side. 

The Pectineus is a flat and quadrangular muscle ; it arises from the 
pectineal line (peoten, a crest) of the os pubis, and from the surface of 
bone in front of that bone. It is inserted into the line leading from the 
anterior intertrochanteric line to the linea aspera of the femur. 

Relations. — By its anterior surface, with the pubic portion of the fascia 
lata, which separates it from the femoral artery and vein and internal sa- 
phenous vein, and lower down with the profunda artery. By its posterior 
surface, with the capsule of the hip joint, and with the obturator externus and 
adductor brevis, the obturator vessels being interposed. By its external 
border, with the psoas, the femoral artery resting upon the line of interval. 
By its internal border, with the outer edge of the adductor longus. Ob- 
turator hernia is situated directly behind this, muscle, which forms one of 
its coverings. 

The Adductor Longus (adducere, to draw to), the most superficial of 
the three adductors, arises, by a round and thick tendon, from the front 
surface of the os pubis, immediately below the angle ; and assuming a 
flattened and expanded form as it descends, is inserted into the middle 
third of the linea aspera. 

Relations. — By its anterior surface, with the pubic portion of the fascia 
lata, and near its insertion with the femoral artery and vein. By its pos- 
terior surface, with the adductor brevis and magnus, the anterior branches 
of the obturator vessels and nerves, and near its insertion with the pro- 
funda artery and vein. By its outer border, with the pectineus ; and by 
the inner border, with the gracilis. 

The pectineus must be divided near its origin and turned outwards, and 
the adductor longus through its middle, turning its ends to either side, to 
bring into view the adductor brevis. 

The Adductor Brevis, placed beneath the pectineus and adductor 
longus, is fleshy, and thicker than the adductor longus ; it arises from the 
body and ramus of the os pubis, and is inserted into the upper third of the 
linea aspera. 

Relations. — By its anterior surface, with the pectineus, adductor longus, 
and anterior branches of the obturator vessels and nerve. By its posterior 
surface, with the adductor magnus, and posterior branches of the obturator 
vessels and nerve. By its outer border, with the obturator externus, and 
conjoined tendon of the psoas and iliacus. By its inner border, with the 
gracilis and adductor magnus. The adductor brevis is pierced near its 
insertion by the middle perforating artery. 

The adductor brevis may now be divided from its origin and turned 
outwards, or its inner two-thirds may be cut away entirely, when the ad- 
ductor magnus muscle will be exposed in its entire extent. 

The Adductor Magnus is a broad triangular muscle, forming a septum 
of division between the muscles situated on the anterior and those on the 
posterior aspect of the thigh. It arises, by fleshy fibres, from the ramus 
of the pubes and ischium, and from'the side of the tuber ischii ; and radi- 
ating in its passage outwards, is inserted into the whole length of the linea 
aspera, and inner condyle of the femur. The adductor magnus is pierced 



POSTERIOR FEMORAL REGION. 251 

by five openings : the three superior, for the three perforating arteries ; 
and the fourth, for the termination of the profunda. The fifth is the large 
oval opening, in the tendinous portion of the muscle, that gives passage 
to the femoral vessels. 

Relations. — By its anterior surface, with the pectineus, adductor brevis, 
adductor longus, femoral artery and vein, profunda artery and vein, with 
their branches, and with the posterior branches of the obturator vessels and 
nerve. By its posterior surface, with the semi-tendinosus, semj-membra- 
nosus, biceps, and gluteus maximus. By its inner border, with the gra- 
cilis and sartorius. By its upper border, with the obturator externus and 
quadratus femoris. 

The Gracilis (slender) is situated* along the inner border of the thigh. 
It arises by a broad, but very thin tendon, from the body of the os pubis, 
along the edge of the symphysis, and from the margin of the ramus of the 
pubes and ischium; and is inserted, by a rounded tendon, into the inner 
tuberosity of the tibia, beneath the expansion of the sartorius. 

Relations. — By its inner or superficial surface, with the fascia lata, and 
below, with the sartorius and internal saphenous nerve ; the internal sa- 
phenous vein crosses it, lying superficially to the fascia lata. By its outer 
or deep surface, with the adductor longus, brevis, and magnus, and the 
internal lateral ligament of the knee joint, from which it is separated by a 
synovial bursa, common to the tendons of the gracilis and semi-tendinosus. 

Actions. — The iliacus, psoas, pectineus, and adductor longus muscles 
bend the thigh upon the pelvis, and, at the same time, from the obliquity 
of their insertion into the lesser trochanter and linea aspera, rotate the en- 
tire limb outwards ; the pectineus and adductors adduct the thigh power- 
fully ; and from the manner of their insertion into the linea aspera, they 
assist in rotating the limb outwards. The gracilis is likewise an adductor 
of the thigh ; but contributes also to the flexion of the leg, by its attach- 
ment to the inner tuberosity of the tibia. 

Posterior Femoral Region. 
Biceps, Semi-tendinosus, Semi-membranosus. 

Dissection. — Remove the integument and fascia on the posterior part 
of the thigh by two flaps, as on the anterior region, and turn aside the glu- 
teus maximus from the upper part ; the muscles may then be examined. 

The Biceps Femoris (bis, double, xscpuXr), head) arises by two heads, 
one by a common tendon with the semi-tendinosus ; the other muscular 
and much shorter, from the lower two-thirds of the external border of the 
linea aspera. This muscle forms the outer hamstring, and is inserted by a 
strong tendon into the head of the fibula ; a portion of the tendon is con- 
tinued downwards into the fascia of the leg, and another is attached to the 
outer tuberosity of the tibia. 

Relations. — By its superficial or posterior surface with the gluteus maxi- 
mus and fascia lata. By its deep or anterior surface with the semi-mem- 
branosus, adductor magnus, vastus externus, the great sciatic nerve, pop- 
liteal artery and vein, and near its insertion with the external head of the 
gastrocnemius, and plantaris. By its inner border with the semi-tendi- 
nosus, and in the popliteal space with the popliteal artery and vein. 

The Semi-tendinosus, remarkable for its long tendon, arises in common 
with the long head of the biceps, from the tuberosity of the ischium ; the 



252 



SEMI-MEMBRANOSUS. 



Fig. 131.* 



two muscJes being closely united for several inches below their origin. It 
is inserted into the inner tuberosity of the tibia. 

Relations. — By its superficial surface- with the glu- 
teus maximus, fascia lata, and at its insertion with the 
synovial bursa which separates its tendon from the ex- 
pansion of the sartorius. By its deep surface with the 
semi-membranosus, adductor magnus, internal head 
of the gastrocnemius, and internal lateral ligament of 
the knee joint, the synovial bursa common to it and 
the tendon of the gracilis being interposed. By its 
inner border with the gracilis ; and by its outer border 
with the biceps. . 

These two muscles must be dissected from the tube- 
rosity of the ischium, to bring into view the origin of 
the next. 

The Semi-membranosus, remarkable for the tendi- 
nous expansion upon its anterior and posterior surface, 
arises from the tuberosity of the ischium, in front of 
the common origin of the two preceding muscles. It 
is inserted into the posterior part of the inner tuberosity 
of the tibia ; at its insertion the tendon splits into three 
portions, one of which is inserted in a groove on the 
inner side of the head of the tibia, beneath the internal 
lateral ligament. The second is continuous with an 
aponeurotic expansion that binds down, the popliteus 
muscle, the popliteal fascia ; and the third turns up- 
wards and outwards to the external condyle of the 
femur, forming the middle portion of the posterior 
ligament of the knee joint (ligamentum posticum 
Winslowii). 

The tendons of the last two muscles, viz. the semi-ten dinosus and 
semi-membranosus, with those of the gracilis and sartorius, form the 
inner hamstring. 

Relations. — By its superficial surface with the gluteus maximus, biceps, 
semi-tendinosus, fascia lata, and at its insertion with the tendinous expan- 
sion of the sartorius. By its deep surface with the quadratus femoris, ad- 
ductor magnus, internal head of the gastrocnemius, the knee joint, from 
which it is separated by a synovial membrane, and the popliteal artery 
and vein. By its inner border with the gracilis. By its outer border with 
the great ischiatic nerve, and in the popliteal space with the popliteal 
artery and vein. 

If the semi-membranosus muscle be turned down from its origin, the 
student will bring into view the broad and radiated expanse of the adduc- 
tor magnus, upon which the three flexor muscles above described rest. 
Jictions. — These three hamstring muscles are the direct flexors of the 

*The muscles of the posterior femoral and gluteal region. 1. The gluteus medius. 
2. The gluteus maximus. 3. The vastus externus, covered in by fascia lata. 4. The 
long head of the biceps. 5. Its short head. 6. The semi-tendinosus. 7. The semi- 
membranosus. 8. The gracilis. 9. A part of the inner border of the adductor magnus. 
10. The edge of the sartorius. 11. The popliteal space. 12. The gastrocnemius 
muscle; its two heads. The tendon of the biceps forms the outer hamstring; and the 
sartorius with the tendons of the gracilis; semi-tendinosus, and semi-membranosus, the 
inner hamstring. 




ANTERIOR TIBIAL REGION. 



253 



leg upon the thigh ; and by taking their origin from below, they balance 
the pelvis on the lower extremities. The biceps, from the obliquity of its 
direction, everts the leg when partially flexed, and the semi-tendinosus 
turns the leg inwards when in the same state of flexion. 

Anterior Tibial Region. Fig. 132.* 

Tibialis anticus, 
Extensor longus digitorum, 
Peroneus tertius, 
Extensor proprius pollicis. 

Dissection. — The dissection of the anterior tibial 
region is to be commenced by carrying an incision 
along the middle of the leg, midway between the 
tibia and the fibula, from the knee to the ankle, 
and bounding it inferiorly by a transverse incision 
extending from one malleolus to the other. And 
to expose the tendons on the dorsum of the foot, 
the longitudinal incision maybe carried onwards to 
the outer side of the base of the great toe, and be 
terminated by another incision directed across the 
heads of the metatarsal bones. 

The Tibialis Anticus muscle (flexor tarsi tibialis) 
arises from the upper two-thirds of the tibia, from 
the interosseous membrane, and from the deep 
fascia ; its tendon passes through a distinct sheath 
in the annular ligament, and is inserted into the 
inner side of the internal cuneiform bone, and base 
of the metatarsal bone of the great toe. 

Relations. — By its anterior surface with the deep 
fascia, from which many of its superior fibres arise, 
and with the anterior annular ligament. By its 
posterior surface with the interosseous membrane, 
tibia, ankle joint, and bones of the tarsus with their articulations. By its 
internal surface with the tibia. By the external surface with the extensor 
longus digitorum, extensor proprius pollicis, and the anterior tibial vessels 
and nerve. 

The Extensor Longus Digitorum arises from the head of the tibia, 
from the upper three-fourths of the fibula, from the interosseous mem- 
brane, and from the deep fascia. Below, it divides into four tendons, 
which pass beneath the annular ligament, to be inserted into the second 
and third phalanges of the four lesser toes. The mode of insertion of the 
extensor tendons, both in the hand and in the foot, is remarkable : each 
tendon spreads into a broad aponeurosis over the first phalanx ; this 
aponeurosis divides into three slips ; the middle one is inserted into the 

* The muscles of the anterior tibial region. 1. The extensor muscles inserted into 
the patella. 2. The subcutaneous surface, of the tibia. 3. The tibialis anticus. 4. The 
extensor longus digitorum. 5. The extensor proprius pollicis. 6. Tlje peroneus tertius. 
7. The peroneus longus. 8. The peroneus brevis. 9, 9. The borders of the solens 
muscle. 10. A part of the inner belly of the gastrocnemius. 11. The extensor brevis 
digitorum ; the tendon in front of this number is that of the peroneus tertius ; and that 
behind it. the tendon of the peroneus brevis. 

22 




254 POSTERIOR TIBIAL REGION. 

base of the second phalanx, and the two lateral slips are continued on- 
wards, to be inserted into the base of the third. 

Relations. — By its anterior surface with the deep fascia of the leg and 
foot, and with the anterior annular ligament. By its posterior surface with 
the interosseous membrane, fibula, ankle joint, extensor brevis digitorum 
which separates its tendons from the tarsus, and with the metatarsus and 
phalanges. By its inner surface with the tibialis anticus, extensor pro- 
prius pollicis, and anterior tibial vessels. By its outer border with the 
peroneus longus and brevis. 

The Peroneus Tertius (flexor tarsi fibularis) arises from the lower 
fourth of the fibula, and is inserted into the base of the metatarsal bone of 
the little toe. Although apparently but a mere division or continuation 
of the extensor longus digitorum, this muscle may be looked upon as 
analogous to the flexor carpi ulnaris of the fore-arm. Sometimes it is alto- 
gether wanting. 

The Extensor Proprius Pollicis lies between the tibialis anticus and 
extensor longus digitorum. It arises from the lower two-thirds of the 
fibula and interosseous membrane. Its tendon passes through a distinct 
sheath in the annular ligament, and is inserted into the base of the last 
phalanx of the great toe. 

Relations. — By its anterior surface, with the deep fascia of the leg and 
foot, and with the anterior annular ligament. By its posterior surface, 
with the interosseous membrane, the fibula, the tibia, the ankle joint, the 
extensor brevis digitorum, and the bones and articulations of the great toe. 
It is crossed upon this aspect by the anterior tibial vessels and nerve. By 
its outer side, with the extensor longus digitorum, and in the foot with the 
dorsalis pedis artery and veins ; the outer side of its tendon upon the dor- 
sum of the foot being the guide to those vessels. By its inner side, with 
the tibialis anticus, and with the anterior tibial vessels. 

Actions. — The tibialis anticus and peroneus tertius are direct flexors of 
the tarsus upon the leg ; acting in conjunction with the tibialis posticus, 
they direct the foot inwards, and with the peroneus longus and brevis, 
outwards. They assist also in preserving the flatness of the foot during 
progression. The extensor longus digitorum and extensor proprius pollicis, 
are direct extensors of the phalanges ; but, continuing their action, they 
assist the tibialis anticus and peroneus tertius in flexing the entire foot 
upon the leg. Taking their origin from below, they increase the stability 
of the ankle joint. 

Posterior Tibial Region. 

Superficial Group. 

Gastrocnemius, 

Plantaris, 

Soleus. 

Dissection. — Make an incision from the middle of the popliteal space, 
down the middle of the posterior part of the leg to the heel, bounding it 
inferiorly by a transverse incision, passing between the two malleoli. Turn 
aside the flaps of integument, and remove the fasciae from the whole of 
this region ; the gastrocnemius muscle will then be exposed. 

The Gastrocnemius (yaovpoxvVov, the bellied part of the leg) arises, 
by two heads, from the two condyles of the femur, the inner head being 



PLANTARIS — SOLEUS. 



255 



the longest. They unite to form the beautiful muscle so Fig. 133 * 

characteristic of this region of the limb. It is inserted, 

by means of the tendo Achillis, into the lower part of 

the posterior tuberosity of the os calcis, a synovial bursa 

being placed between that tendon and the upper part of 

the tuberosity. The gastrocnemius must be removed 

from its origin, and turned down, in order to expose the 

next muscle. 

Relations. — By its superficial surface, with the deep 
fascia of the leg, which separates it from the external 
saphenous vein, and with the external saphenous nerve. 
By its deep surface, with the lateral portions of the pos- 
terior ligament of the knee joint, the popliteus, plantaris, 
and soleus. The internal head of the muscle rests 
against the posterior surface of the internal condyle of 
the femur ; the external head against the outer side of 
the external condyle. In the latter, a sesamoid bone is 
sometimes found. 

The Plantaris (planta, the sole of the foot), an ex- 
tremely diminutive muscle, situated between the gastroc- 
nemius and soleus, arises from the outer condyle of 
the femur ; and is inserted, by its long and delicately 
slender tendon, into the inner, side of the posterior 
tuberosity of the os calcis, by the side of the tendo 
Achillis : having crossed obliquely between the two 
muscles. 

The Soleus (solea, a sole), is the broad muscle upon 
which the plantaris rests. It arises, from the head and 
upper third of the fibula, from the oblique line and middle third of the 
tibia. Its fibres converge to the tendo Achillis, by which it is inserted into 
the posterior tuberosity of the os calcis. Between the fibular and tibial 
origins of this muscle is a tendinous arch, beneath which the popliteal 
vessels and nerve pass into the leg. 

Relations. — By its superficial surface, with the gastrocnemius and plan- 
taris. By its deep surface, with the intermuscular fascia, which separates 
it from the flexor longus digitorum, tibialis posticus, flexor longus pollicis, 
from the posterior tibial vessels and nerve, and from the peroneal vessels. 

Actions. — The three muscles of the calf draw powerfully on the os cal- 
cis, and lift the heel ; continuing their action, they raise the entire body. 
This action is attained by means of a lever of the second power, the ful- 
crum (the toes) being at one end, the weight (the body supported on the 
tibia) in the middle, and the power (these muscles) at the other extremity. 

They are, therefore, the walking muscles, and perform all movements 
that require the support of the whole body from the ground, as dancing, 
leaping, &c. Taking their fixed point from below, they steady the leg 
upon the foot. 

* The superficial muscles of the posterior aspect of the leg. 1. The biceps muscle 
forming the outer hamstring. 2. The tendons forming the inner hamstring. 3. The 
popliteal space. 4. The gastrocnemius muscle. 5, 5. The soleus. 6. The tendo Achillis. 
7. The posterior tuberosity of the os calcis. 8. The tendons of the peroneus longus and 
brevis muscles passing behind the outer ankle. 9. The tendons of the tibialis posticus 
and flexor longus digitorum. passing into the foot behind the inner ankle. 



256 



FLEXOR LONGUS DIGITORUM. 



Deep Layer. 

Popliteus, 

Flexor longus pollicis, 
Flexor longus digitorum, 
Tibialis posticus. 

Dissection. — After the removal of the soleus, the deep layer will be found 
bound down by an intermuscular fascia which is to be dissected away ; 
the muscles may then be examined. 

The Popliteus muscle (poples, the ham of the leg) forms the floor of 
the popliteal region at its lower part, and is bound tightly down by a strong 
fascia derived from the middle slip of the tendon of the semi-membranosus 
muscle. It arises by a rounded tendon from a deep groove on the outer 
Fig. 134.* s ^ e °f tne external condyle of the femur, beneath the ex- 
ternal lateral ligament ; and spreading obliquely over the 
head of the tibia, is inserted into the surface of bone above 
its oblique line. This line is called, from being the limit 
of insertion of the popliteal muscle, the popliteal line. 

Relations. — By its superficial surface with a thick fascia 
which separates it from the two heads of the gastrocne- 
mius, the plantaris, and the popliteal vessels and nerve. 
By its deep surface with the synovial membrane of the knee 
joint and with the upper part of the tibia. 

The Flexor Longus Pollicis is the most superficial 
of the next three muscles. It arises from the lower two- 
thirds of the fibula, and passes through a groove in the 
astragalus and os calcis, which is converted by tendinous 
fibres into a distinct sheath lined by a synovial mem- 
brane, into the sole of the foot ; it is inserted into the base 
of the last phalanx of the great toe. 

Relations. — By its superficial surface with the intermus- 
cular fascia, which separates it from the soleus and tendo 
Achillis. By its deep surface w T ith the tibialis posticus, 
fibula, fibular vessels, interosseous membrane, and ankle 
joint. By its outer border with the peroneus longus 
By its inner border with the flexor longus 
In the foot, the tendon of the flexor longus 
connected with that of the flexor longus 
digitorum by a short tendinous slip. 

The Flexor Longus Digitorum (perforans) arises 
from the surface • of the tibia, immediately below the popliteal line. Its 
tendon passes through a sheath common to it and the tibialis posticus be- 
hind the inner malleolus ; it then passes through a second sheath which is 

* The deep layer of muscles of the posterior tibial region. 1. The lower extremity 
of the femur. 2. The ligamentum posticum Winslowii. 3. The tendon of the semi- 
membranosus muscle dividing into its three slips. 4. The internal lateral ligament of 
the knee joint. 5. The external lateral ligament. 6. The popliteus muscle. 7. The 
flexor longus digitorum. 8. The tibialis posticus. 9. The flexor longus pollicis. 1". 
The peroneus longus muscle. 1 1. The peroneus brevis. 12. The tendo Achillis divided 
near its insertion into the os calcis. 13. The tendons of the tibialis posticus and flexor 
longus digitorum muscles, just as they are about to pass beneath the internal annular 
ligament of the ankle; the interval between the latter tendon and the tendon of the 
flexor longus pollicis is occupied by the posterior tibial vessels and nerve. 



and brevis. 
digitorum. 



pollicis 



is 



FIBULAR REGION. 257 

connected with a groove in the astragalus and os calcis, into the sole of 
the foot, where it divides into four tendons, which are inserted into the 
base of the last phalanx of the four lesser toes, perforating the tendons of 
the flexor brevis digitorum. 

Relations.— By its superficial surface with the intermuscular fascia, 
which separates it from the soleus, and with the posterior tibial vessels and 
nerve. By its deep surface with the tibia and tibialis posticus. In the sole 
of the foot its tendon is in relation with the abductor pollicis and flexor 
brevis digitorum, which lie superficially to it, and it crosses the tendon of 
the flexor longus pollicis. At the point of crossing it receives the tendi- 
nous slip of communication from the latter. 

The flexor longus pollicis must now be removed from its origin, and 
the flexor longus digitorum drawn aside, to bring into view the entire ex- 
tent of the tibialis posticus. 

The Tibialis Posticus (extensor tarsi tibialis) lies upon the interosseous 
membrane, between the two bones of the leg. It arises by two heads from 
the adjacent sides of the tibia and fibula their whole length, and from the 
interosseous membrane. Its tendon passes inwards beneath the tendon 
of the flexor longus digitorum, and runs in the same sheath ; it then passes 
through a proper sheath over the deltoid ligament, and beneath the calca- 
neo-scaphoid articulation to be inserted into the tuberosity of the scaphoid 
and internal cuneiform bone. While in the common sheath behind the 
internal malleolus, the tendon of the tibialis posticus lies internally to that 
of the flexor longus digitorum, from which it is separated by a thin fibrous 
partition. A sesamoid bone is usually met with in the tendon close to its 
insertion. 

Relations. — By its superficial surface with the intermuscular septum, 
the flexor longus pollicis, flexor longus digitorum, posterior tibial vessels 
and nerve, peroneal vessels, and in the sole of the foot with the abductor 
pollicis. By its deep surface with the interosseous membrane, the fibula 
and tibia, the ankle joint, and the astragalus. The anterior tibial artery 
passes between the two heads of the muscle. 

The student will observe that the two latter muscles change their rela- 
tive position to each other in their course. Thus, in the leg, the position 
of the three muscles from within outwards, is, flexor longus digitorum, 
tibialis posticus, flexor longus pollicis. At the inner malleolus, the rela- 
tion of the tendons is, tibialis posticus, flexor longus digitorum, both 
in the same sheath ; then a broad groove, which lodges the posterior 
tibial artery, venae comites, and nerve ; and lastly, the flexor longus 
pollicis. 

Actions. — The popliteus is a flexor of the tibia upon the thigh, carrying 
it at the same time inwards, so as to invert the leg. The flexor longus 
pollicis and flexor longus digitorum are the long flexors of the toes ; their 
tendons are connected in the foot by a short tendinous band, hence they 
necessarily act together. The tibialis posticus is an extensor of the tarsus 
upon the leg, and an antagonist to the tibialis anticus. It combines with 
the tibialis anticus in adduction of the foot. 

Fibular Region. 

Peroneus longus, 
Peroneus brevis. 

22* r 



258 FOOT — DORSAL REGION. 

Dissection. — These muscles are exposed by continuing the dissection 
of the anterior tibial region outwards beyond the fibula, to the border of 
the posterior tibial region. 

The Peroneus Longus (ir*£ov*j, fibula, extensor tarsi fibularis longior) 
muscle arises from the head and upper third of the outer side of the fibula, 
and terminates in a long tendon, which passes behind the external mal- 
leolus, and obliquely across the sole of the foot, through the groove in the 
cuboid bone, to be inserted into the base of the metatarsal bone of the 
great toe. Its tendon is thickened where it glides behind the external 
malleolus, and a sesamoid bone is developed in that part which plays 
upon the cuboid bone. 

Relations. — By its superficial surface with the fascia of the leg and foot. 
By its deep surface with the fibula, peroneus brevis, os calcis, and cuboid 
bone, and near the head of the fibula with the fibular nerve. By its ante- 
rior border it is separated from the extensor longus digitorum by the 
attachment of the fascia of the leg to the fibula ; and by the posterior 
border by the same medium from the soleus and flexor longus pollicis. 
The peroneus longus is furnished with three tendinous sheaths and as 
many synovial membranes ; the first is situated behind the external mal- 
leolus, and is common to this muscle and the peroneous brevis, the second 
on the outer side of the os calcis, and the third on the cuboid bone. 

The Peroneus Brevis (extensor tarsi fibularis brevior) lies beneath the 
peroneus longus ; it arises from the lower half of the fibula, and terminates 
in a tendon which passes behind the external malleolus and through a 
groove in the os calcis, to be inserted into the base of the metatarsal bone 
of the little toe. 

Relations. — By its superficial surface with the peroneus longus and 
fascia of the leg and foot. By its deep surface with the fibula, the os 
calcis, and cuboid bone. The lateral relations are the same as those of 
the peroneus longus. The tendon of the peroneus brevis has but two 
tendinous sheaths and two synovial membranes, one behind the external 
malleolus and common to both peronei, the other upon the side of the os 
calcis. 

Actions. — The peronei muscles are extensors of the foot, conjointly 
with the tibialis posticus. They antagonize the tibialis anticus and pero- 
neus tertius, which are flexors of the foot. The whole of these muscles 
acting together, tend to maintain the flatness of the foot, so necessary to 
security in walking. 

FOOT. 

Dorsal Region. 
Extensor brevis digitorum, Interossei dorsales. 

The Extensor Brevis Digitorum muscle arises from the outer side of 
the os calcis, crosses the foot obliquely, and terminates in four tendons, 
the innermost of which is inserted into the base of the first phalanx of the 
great toe, and the other three into the sides of the long extensor tendons 
of the second, third, and fourth toes. 

Relations. — By its upper surface with the tendons of the extensor longus 
digitorum, peroneus brevis, and with the deep fascia of the foot. By its 
under surface with the tarsal and metatarsal bones. Its inner border is in 
relation with the dorsal is pedis artery, and the innermost tendon of the 
muscle crosses that artery just before its division. 



PLANTAR REGION. 



259 



The Dorsal Interossei muscles are placed between the metatarsal 
oones ; they resemble the analogous muscles in the hand in arising by 
two heads from the adjacent sides of the metatarsal bones ; their tendons 
are inserted into the base of the first phalanx, and into the digital expan- 
sion of the tendons of the long extensor. 

The first dorsal interosseous is inserted into the inner side of the second 
toe, and is therefore an adductor ; the other three are inserted into the 
outer side of the second, third, and fourth toes, and are consequently 
abductors. 

Relations. — By their upper surface with a string fascia which separates 
them from the extensor tendons. By their under surface with the plantar 
interossei. Each of the muscles gives passage to a small artery (posterior 
perforating) which communicates with the external plantar artery. And 
between the heads of the first interosseous muscle the communicating 
artery of the dorsalis pedis takes its course. 



Fig. 135.* 



Fig. 136.f 





Plantar Region. 
First Layer. 
Abductor pollicis, 
Abductor minimi digiti, 
Flexor brevis digitorum. 
Dissection. — The sole of the foot is best dissected by carrying an inci- 
sion around the heel, and along the inner and outer borders of the foot, to 

* Dorsal interossei. 1. Abductor secundi. 2. Adductor secundi. 3. Adductor tertii. 

4. Adductor quarti. 

■J- The first layer of muscles in the sole of the foot; this layer is exposed by the re- 
moval of the plantar fascia. 1. The os calcis. 2. The posterior part of the plantar 
fascia divided transversely. 3. The abductor pollicis. 4. The abductor minimi digiti. 

5. The flexor brevis digitorum. 6. The tendon of the flexor longus pollicis muscle. 
7, 7. The lumbricales. On the second and third toes, the tendons of the flexor longus 
digitorum are seen passing through the bifurcation of the tendons of the flexor brevis 
digitorum. 



260 



MUSCLES OF THE SOLE OF THE FOOT. 



Fig. 137.* 



the great and little toes. This incision should divide the integument and 
superficial fascia, and both together should be dissected from the deep 
fascia, as far forward as the base of the phalanges, where they may be re- 
moved from the foot altogether. The deep fascia should then be removed, 
and the first layer of muscles will be brought into view. 

The Abductor Pollicis lies along the inner border of the foot ; it arises 
by two heads, between which the tendons of the long flexors, arteries, 
veins, and nerves enter the sole of the foot. One head arises from the 
inner tuberosity of the os calcis, the other from the internal annular liga- 
ment and plantar fascia.* Insertion, into the base of the first phalanx of 
the great toe, and into the internal sesamoid bone. 

Relations. — By its superficial surface with the internal portion of the 
plantar fascia. By its deep surface with the flexor brevis pollicis, musculus 
accessorius, tendons of the flexor longus digitorum and flexor longus pol- 
licis, tendons of the tibialis anticus and posticus, the plantar vessels and 
nerves, and the tarsal bones. On its outer border with the flexor brevis 
digitorum, from which it is separated by a vertical septum of the plantar 
fascia. 

The Abductor Minimi Digiti lies along the outer 
border of the sole, of the foot. It arises from the outer 
tuberosity of the os calcis, and from the plantar fascia, 
as far forward as the base of the fifth metatarsal bone, 
and is inserted into the base of the first phalanx of the 
little toe. 

Relations. — By its superficial surface with the ex- 
ternal portion of the plantar fascia. By its deep sur- 
face with the musculus accessorius, flexor brevis 
minimi digiti, with the tarsal bones, and with the 
metatarsal bone of the little toe. By its inner side 
with the flexor brevis digitorum, from which it is se- 
parated by the vertical septum of the plantar fascia. 

The Flexor Brevis Digitorum (perforatus) is 
placed between the two preceding muscles. It arises 
from the under surface of the os calcis, from the 
plantar fascia and intermuscular septa, and is inserted 
by four tendons into the base of the second phalanx 
of the four lesser toes. Each tendon divides, pre- 
viously to its insertion, to give passage to the tendon 
of the long flexor ; hence its cognomen perforatus. 
Relations. — By its superficial surface with the plantar fascia. By its 
deep surface with a thin layer of fascia which separates it from the muscu- 
lus accessorius, tendons of the flexor longus digitorum and flexor longus 
pollicis, and plantar vessels and nerves. By its borders with the vertical 
septa of the plantar fascia, which separate the muscle, on the one side 
from the abductor pollicis, and on the other from the abductor minimi 
digiti. 

* The third and a part of the second layer of muscles of the sole of the foot. 1. The 
divided edge of the plantar fascia. 2. The musculus accessorius. 3. The tendon of the 
flexor longus digitorum. 4. The tendon of the flexor longus pollicis. 5. The flexor 
brevis pollicis." 6. The adductor pollicis. 7. The flexor brevis minimi digiti. 8. The 
transversus pedis. 9. Interossei muscles, plantar and dorsal. 10. Convex ridge formed 
by the tendon of the peroneus longus muscle in its oblique course across the foot. 




MUSCLES OF THE SOLE OF THE FOOT. 



261 



Second Layer. 



Musculus accessorius, 



Lumbricales. 



Dissection. — The three preceding muscles must be divided from their 
origin, and anteriorly through their tendons, and removed, in order to 
bring into view the second layer. 

The Musculus Accessorius arises by two slips from either side of the 
under surface of the os calcis ; the inner slip being fleshy, the outer, ten- 
dinous. The muscle is inserted into the outer side and upper surface of 
the tendon of the flexor longus digitorum. 

Relations. — By its superficial surface, with the three muscles of the 
superficial layer, from which it is separated by their fascial sheaths, and 
with the external plantar vessels and nerves. By its deep surface, with 
the under surface of the os calcis and the long calcaneo-cuboid ligament. 

The Lumbricales (lumbricus, an earthworm) are four little muscles, 
arising from the tibial side of the tendons of the flexor longus digitorum, 
and inserted into the expansion of the extensor tendons, and into the base 
of the first phalanx of the four lesser toes. 

Relations. — By their superficial surface, with the Fig. 138* 

tendons of the flexor brevis digitorum. By their deep 
surface, with the third layer of muscles of the sole of 
the foot. They pass between the digital slips of the 
deep fascia to reach their insertion. 

Third Layer. 

Flexor brevis pollicis, 
Adductor pollicis, 
Flexor brevis minimi digiti, 
Transversus pedis. 

Dissection. — The tendons of the long flexors, and 
the muscles connected with them, must be removed, 
to see clearly the attachments of the third layer. 

The Flexor Brevis Pollicis arises, by a pointed 
tendinous process, from the side of the cuboid, and 
from the external cuneiform bone ; it is inserted, by 
two heads, into the base of the first phalanx of the 
great toe. Two sesamoid bones are developed in the 
tendons of insertion of these two heads, and the tendon of the flexor longus 
pollicis lies in the groove between them. 

Relations. — By its superficial surface, with the abductor pollicis, tendon 
of the flexor longus pollicis, and plantar fascia. By its deep surface, with 
the tarsal bones and their ligaments, the metatarsal bone of the great toe, 
and the insertion of the tendon of the peroneus longus. By its inner bor- 
der, with the abductor pollicis ; and by its outer border, with the adductor 
pollicis ; with both of these muscles it is blended near its insertion. 

The Adductor Pollicis arises from the cuboid bone, from the sheath 
of the tendon of the peroneus longus, and from the base of the third and 

* Deep-seated muscles in the sole of the foot. 1. Tendon of the flexor longus pollicis. 
2. Tendon of the flexor communis digitorum pedis. 3. Flexor accessorius. 4, 4. Lum- 
bricales. 5. Flexor brevis digitorum. 6. Flexor brevis pollicis pedis. 7. Flexor brevis 
minimi digiti pedis. 




262 MUSCLES OF THE SOLE OF THE FOOT. 

fourth metatarsal bones. It is inserted into the base of the first phalanx 
of the great toe. 

Relations. -— By its superficial surface, with the tendons of the flexor 
longus and flexor brevis digitorum, the musculus accessorius, and lumbri- 
cales. By its deep surface, with the tarsal bones and ligaments, the exter- 
nal plantar artery and veins, the interossei muscles, tendon of the peroneus 
longus, and metatarsal bone of the great toe. By its inner border, with the 
flexor brevis pollicis ; with which its fibres are blended. 

The Flexor Brevis Minimi Digiti aiises from the base of the metatar- 
sal bone of the little toe, and from the sheath of the tendon of the peroneus 
longus. It is inserted into the base of the first phalanx of the little toe. 

Relations. — By its superficial surface, with the tendons of the flexor 
longus and flexor brevis digitorum, the fourth lumbricalis, abductor 
minimi digiti, and plantar fascia. By its deep surface, with the plantar 
interosseous muscle of the fourth metatarsal space, and the metatarsal 
bone. 

The Transversus Pedis arises, by fleshy slips, from the heads of the 
metatarsal bones of the four lesser toes. Its tendon is inserted into the 
base of the first phalanx of the great toe, being blended with that of the 
adductor pollicis. 

Relations. — By its superficial surface, with the tendons of the flexor 
longus and flexor brevis digitorum, and the lumbricales. By its deep 
surface, with the interossei, and heads of the metatarsal bones. 

Fourth Layer. 
Interossei plantares. 

The Plantar Interossei muscles are three in number, and are placed 
upon, rather than between, the metatarsal bones. They arise from the 
base of the metatarsal bones of the three outer toes, and are inserted into 
the inner side of the extensor tendon and base of the first phalanx of the 
same toes. 

Relations. — By their superficial surface, with the dorsal interossei and 
the metatarsal bones. By their deep surface, with the external plantar 
artery and veins, the adductor pollicis, transversus pedis, and flexor mi- 
nimi digiti. 

Jiclions. — All the preceding muscles act upon the toes ; and the move- 
ments which they are capable of executing may be referred to four heads, 
viz., flexion, extension, adduction, and abduction. In these actions they 
are grouped in the following manner : — 

Flexion. Extension. 

Flexor longus digitorum, Extensor longus digitorum, 

Flexor brevis digitorum, Extensor brevis digitorum. 

Flexor accessorius, 
Flexor minimi digiti. 

Jidduction. Jibduction. 

Interossei \ one dorsal, Interossei, three dorsal, 

' I three plantar. Abductor minimi digiti. 



THE FASCIAE. 



263 



The great toe, like the thumb in the hand, enjoys an 
independent action, and is provided with distinct mus- 
cles to perform its movements. These movements are 
precisely the same as those of the other toes, viz. : 

Flexion. 

Flexor longus pollicis, 
Flexor brevis pollicis. 

Extension. 

Extensor proprius pollicis, 
Extensor brevis digitorum. 

Adduction. 
Adductor pollicis. 

Abduction. 
Abductor pollicis. 

The only muscles excluded from this table are the 
lumbricales, four small muscles, which, from their at- 
tachments to the tendons of the long flexor, appear to 
be assistants to its action ; and the transversus pedis, a small 
placed transversely in the foot across the heads of the metatarsal 
which has for its office the drawing together of the toes. 




muscle 
bones, 



CHAPTER V. 



ON THE FASCIAE. 



Fascia (fascia, a bandage) is the name assigned to laminae of various 
extent and thickness, which are distributed through the different regions 
of the body, for the purpose of investing or protecting the softer and more 
delicate organs. From a consideration of their structure, these fasciae may 
be arranged into two groups : cellulo-fibrous fascia;, and aponeurotic 
fasciae. 

The cellulo-fibrous fascia is best illustrated in the common subcutaneous 
investment of the entire body, the superficial fascia. This structure is si- 
tuated immediately beneath the integument over every part of the frame, 
and is the medium of connexion between that layer and the deeper parts. 
It is composed of cellulo-fibrous tissue containing in its areolae an abun- 
dance of adipose cells. The fat being a bad conductor of caloric, serves 
to retain the warmth of the body ; while it forms at the same time a yield- 
ing tissue, through which the minute vessels and nerves pass to the papil- 
lary layer of the skin, without incurring the risk of obstruction from injury 
or pressure upon the surface. By dissection, the superficial fascia may be 
separated into two layers, between which are found the superficial or cu- 

• Plantar interossei. 1. Abductor tertii. 2. Abductor quarti. 3. Interosseous minimi 
digui. 




264 FASCIAE OF THE HEAD AND NECK. 

taneous vessels and nerves ; as the superficial epigastric artery, the saphe- 
nous veins, the radial and ulnar veins, the superficial lymphatic vessels, 
also the cutaneous muscles, as the platysma myoides, orbicularis palpe- 
brarum, sphincter ani, &c. In other situations, the cellulo-fibrous fascia 
is found condensed into a strong and inelastic membrane, as is exemplified 
in the deep fascia of the neck, the thoracic, transversalis, and perineal 
fasciae, and the sheaths of vessels. 

The aponeurotic fascia is the strongest kind of investing membrane ; it 
is composed of tendinous fibres, running parallel with each other, and 
connected by other fibres of the same kind passing in different directions. 
When freshly exposed, it is brilliant and nacreous, and is tough, inelastic, 
and unyielding. In the limbs it forms the deep fascia, enclosing and 
forming distinct sheaths to all the muscles and tendons. It is thick upon 
the outer and least protected side of the limb, and thinner upon its inner 
side. It is firmly connected to the bones, and to the prominent points of 
each region, as to the pelvis, knee, and ankle, in the lower, and to the 
clavicle, scapula, elbow T , and wrist, in the upper extremity. It assists the 
muscles in their action, by keeping up a tonic pressure on their surface ; 
aids materially in the circulation of the fluids in opposition to the laws of 
gravity ; and in the palm of the hand and sole of the foot is a powerful 
protection to the structures which enter into the composition of these re- 
gions. In some situations its tension is regulated by muscular action, as 
by the tensor vaginae femoris and gluteus maximus in the thigh, by the 
biceps in the leg, and by the biceps and palmaris longus in the arm ; in 
other situations it affords an extensive surface for the origin of the fibres 
of muscles. 

The fasciae may be arranged like the other textures of the body into, 1. 
Those of the head and neck. 2. Those of the trunk. 3. Those of the 
upper extremity. 4. Those of the lower extremity. 

FASCIA OF THE HEAD AND NECK. 

The Temporal Fascia is a strong aponeurotic membrane which covers 
in the temporal muscle at each side of the head, and gives origin by its 
internal surface to some of its muscular fibres. It is attached to the whole 
extent of the temporal ridge above, and to the zygomatic arch below ; in 
the latter situation it is thick and divided into two layers, the external 
being connected to the upper border of the arch, and the internal to its 
inner surface. A small quantity of fat is usually found between these two 
layers, together with the orbital branch of the temporal artery. 

Cervical Fascia. — The fasciae of the neck are the superficial and the 
deep. The superficial cervical fascia is a part of the common superficial 
fascia of the entire body, and is only interesting from containing between 
its layers the platysma myoides muscle. 

The deep cervical fascia is a strong cellulo-fibrous layer which invests 
the muscles of the neck, and retains and supports the vessels and nerves. 
It commences posteriorly at the ligamentum nuchas, and passes forwards 
at each side beneath the trapezius muscle to the posterior border of the 
sterno-mastoid ; here it divides into two layers, which embrace that muscle 
and unite upon its anterior border to be prolonged onwards to the middle 
line of the neck, where it becomes continuous with the fascia of the oppo- 
site side. Besides thus constituting a sheath for the sterno-mastoid, it 



FASCLE OF THE TRUNK. 



265 



Fig. 140 * 



also forms sheaths for the other muscles of the neck over which it passes. 
If the superficial layer of the sheath of the sterno-mastoid be traced up- 
wards, it will be found to pass over the parotid gland and masseter muscle, 
and to be inserted into the zygomatic 
arch ; and if it be traced downwards, it 
will be seen to pass in front of the clavi- 
cle, and become lost upon the pectoralis 
major muscle. If the deep layer of the 
sheath be examined superiorly, it will be 
found attached to the styloid process, 
from which it is reflected to the angle of 
the lower jaw, forming the stylo-maxil- 
lary ligament ; and if it be followed 
dow T n wards, it will be found connected 
with the tendon of the omo-hyoid mus- 
cle, and may thence be traced behind 
the clavicle, where it encloses the sub- 
clavius muscle, and, being extended 
from the cartilage of the first rib to the 
coracoid process, constitutes the costo- 
coracoid membrane. In front of the sterno-mastoid muscle, the deep 
fascia is attached to the border of the lower jaw and oshyoides, and forms 
a distinct sheath for the submaxillary gland. Inferiorly it divides into two 
layers, one of which passes in front -of the sternum, while the other is at- 
tached to its superior border. 




FASCIA OF THE TRUNK. 

The thoracic fascia] is a dense layer of cellulo-fibrous membrane, 
stretched horizontally across the superior opening of the thorax. It is 
firmly attached to the concave margin of the first rib, and to the inner 
surface of the sternum. In front it leaves an opening for the connexion 
of the cervical with the thoracic portion of the thymus gland, and behind 
it forms an arch across the vertebral column, to give passage to the 
oesophagus. 

At the point where the great vessels and trachea pass through the tho- 
racic fascia, it divides into an ascending and descending layer. The 

* A transverse section of the neck, showing the deep cervical fascia and its numerous 
prolongations, forming sheaths for the different muscles. As the figure is symmetrical, 
the figures of reference are placed only on one side. 1. The platysma myoides. 2. 
The trapezius. 3. The ligamentum nuchse, from 'which the fascia may be traced for- 
wards beneath the trapezius, enclosing the other muscles of the neck. 4. The point at 
which the fascia divides, to form a sheath for the sterno-mastoid muscle (5). 6. The 
point of reunion of the two layers of the sterno-mastoid sheath. 7. The point of union 
of the deep cervical fascia of opposite sides of the neck. 8. Section of the sterno-hyoid. 
9. Omo-hyoid. 10. Sterno-thyroid. 11. The lateral lobe of the thyroid gland. 12. The 
trachea. 13. The oesophagus. 14. The sheath containing the common carotid artery, 
internal jugular vein, and pneumogastric nerve. 15. The longus colli. The nerve in 
front of the sheath of this muscle is the sympathetic. 16. The rectus anticus major. 
17. Scalenus anticus. 18. Scalenus posticus. 19. The splenius capitis. 20. Splenius 
colli. 21. Levator anguli scapulae. 22. Complexus. 23,Trachelo-mastoid. 24. Trans- 
versalis colli. 25. Cervicalis ascendens. 26. The semi-spinalis colli. 27. The multi- 
fidus spina;. 28. A cervical vertebra. The transverse processes are seen to be traversed 
by the vertebral artery and vein. 

| For an excellent description of this fascia, see Sir Astley Cooper's work on the 
"Anatomy of the Thymus Gland." 

23 



266 ABDOMINAL FASCIAE. 

ascending layer is attached to the trachea, and becomes continuous with 
the sheath of the carotid vessels, and with the deep cervical fascia ; the 
descending layer descends upon the trachea to its bifurcation, surrounds 
the large vessels arising from the arch of the aorta, and the upper part of 
the arch itself, and is continuous with the fibrous layer of the pericardium. 
It is connected also with the venae innominatse and superior cava, and is 
attached to the cellular capsule of the thymus gland. 

"The thoracic fascia," writes Sir Astley Cooper, "performs three im- 
portant offices : — 

" 1st. It forms the upper boundary of the chest, as the diaphragm does 
the lower. 

" 2d. It steadily preserves the relative situation of the parts which enter 
and quit the thoracic opening. 

"3d. It attaches and supports the heart in its situation, through the 
medium of its connexion with the aorta and large vessels which are placed 
at its curvature." 

ABDOMINAL FASCIA. 

The lower part of the parietes of the abdomen, and the cavity of the 
pelvis, are strengthened by a layer of fascia which lines their internal sur- 
face, and at the bottom of the latter cavity is reflected inwards to the sides 
of the bladder. This fascia is continuous throughout the whole of the 
above-mentioned surface ; but for convenience of description is considered 
under the several names of transversalis fascia, iliac fascia, and pelvic 
fascia ; the two former meet at the crest of the ilium and Poupart's liga- 
ment, and the latter is confined to the cavity of the true pelvis. 

The fascia transversalis (Fascia Cooperi)* is a cellulo-fibrous lamella, 
which lines the inner surface of the transversalis muscle. It is thick and 
dense below, near the lower part of the abdomen ; but becomes thinner 
as it ascends, and is gradually lost in the subserous cellular tissue. It is 
attached inferiorly to the reflected margin of Poupart's ligament and to the 
crest of the ilium; internally, to the border of the rectus muscle ; and, at 
the inner third of the femoral arch, is continued beneath Poupart's liga- 
ment, and forms the anterior segment of the crural canal, or sheath of 
the femoral vessels. 

The internal abdominal ring is situated in this fascia, at about midway 
between the spine of the os pubis and the anterior superior spine of the 
ilium, and half an inch above Poupart's ligament ; it is bounded upon its 
inner side by a well-marked falciform border, but is ill defined around its 
outer margin. From the circumference of this ring is given off an infundi- 
buliform process, which surrounds the testicle and spermatic cord, consti- 
tuting the fascia propria of the latter, and forms the first investment to the 
sac of oblique inguinal hernia. It is the strength of this fascia, in the in- 
terval between the tendon of the rectus and the internal abdominal ring, 
that defends this portion of the parietes from the frequent occurrence of 
direct inguinal hernia. 

INGUINAL HERNIA. 

Inguinal hernia is of two kinds, oblique and direct. 

In Oblique Inguinal Hernia the intestine escapes from the cavity of 

* Sir Astley Cooper first described this fascia in its important relation to inguinal 
hernia. 



INGUINAL HERNIA. 267 

the abdomen into the spermatic canal, through the internal abdominal ring, 
pressing before it a pouch of peritoneum which constitutes the hernial sac, 
and distending the infundibuliform process of the transversalis fascia. 
After emerging through the internal abdominal ring, it passes first beneath 
the lower and arched border of the transversalis muscle ; then beneath the 
lower border of the internal oblique muscle ; and finally through the ex- 
ternal abdominal ring in the aponeurosis of the external oblique. From 
the transversalis muscle it receives no investment ; while passing beneath 
the lower border of the internal oblique it obtains the cremaster muscle ; 
and, upon escaping at the external abdominal ring, receives the inter- 
columnar fascia. So that the coverings of an oblique inguinal hernia, 
after it has emerged through the external abdominal ring, are, from the 
surface to the intestine, the 

Integument, Cremaster muscle, 

Superficial fascia, Transversalis, or infundibuliform fascia, 

Intercolumnar fascia, Peritoneal sac. 

The spermatic canal, which, in the normal condition of the abdominal 
parietes serves for the passage of the spermatic cord in the male, and the 
round ligament with its vessels in the female, is about one inch and a 
half in length. It is bounded in front by the aponeurosis of the external 
oblique muscle ; behind by the transversalis fascia, and the conjoined ten- 
don of the internal oblique and transversalis muscle ; above by the arched 
borders of the internal oblique and transversalis ; below by the grooved 
border of Poupart's ligament, and at each extremity by one of the abdo- 
minal rings, the internal ring at the inner termination, the external ring at 
the outer extremity. These relations may be more distinctly illustrated 
by the following plan — 

Above. 

Lower borders of interna] oblique 

and transversalis muscle. 

In Front. 5 Behind, 



Aponeurosis of exter- 
nal oblique. 



Spermatic canal. 



Below. 
Grooved border of 
Poupart's ligament. 



Transversalis fascia. 
Conjoined tendon of 

internal oblique and 

transversalis. 



There are three varieties of oblique inguinal hernia : — common, congen- 
ital, and encysted. 

Common oblique hernia is that which has been described above. 

Congenital hernia results from the nonclosure of the pouch of peritoneum 
carried downwards into the scrotum by the testicle, during its descent in 
the foetus. 

The intestine at some period of life is forced into this "canal, and de- 
scends through it into the tunica vaginalis where it lies in contact with the 
testicle ; so that congenital hernia ha:? no proper sac, but is contained 
within the tunica vaginalis. The other coverings are the same as those 
of common inguinal hernia. 

Encysted hernia (hernia infantilis, of Hey) is that form of protrusion in 
which the pouch of peritoneum forming the tunica vaginalis, being only 
partially closed, and remaining open externally to the abdomen, admits 



268 FASCIA ILIACA — FASCIA PELVICA. 

of the hernia passing into the scrotum, behind the tunica vaginalis. So 
that the surgeon in operating upon this variety, requires to divide three 
layers of serous membrane ; the first and second layers being those of the 
tunica vaginalis ; and the third the true sac of the hernia. 

Direct Inguinal Hernia has received its name from passing directly 
through the external abdominal ring, and forcing before it the opposing 
parietes. This portion of the wall of the abdomen is strengthened by the 
conjoined tendon of the internal oblique and transversalis muscle, which 
is pressed before the hernia, and forms one of its investments. Its cover- 
ings are, the 

Integument, Conjoined tendon, 

Superficial fascia, Transversalis fascia, 

Intercolumnar fascia, Peritoneal sac. 

Direct inguinal hernia differs from oblique in never attaining the same 
bulk, in consequence of the resisting nature of the conjoined tendon of the 
internal oblique and transversalis and of the transversalis fascia ; in its di- 
rection, having a tendency to protrude from the middle line rather than 
towards it. Thirdly, in making for itself a new passage through the ab- 
dominal parietes, instead of following a natural channel ; and fourthly, in 
the relation of the neck of its sac to the epigastric artery ; that vessel lying 
to the outer side of the opening of the sac of direct hernia, and to the 
inner side of that of oblique hernia. 

All the forms of inguinal hernia are designated scrotal, when they have 
descended into that cavity. 

The Fascia Iliaca is the aponeurotic investment of the psoas and iliacus 
muscles ; and, like the fascia transversalis, is thick below, and becomes 
gradually thinner as it ascends. It is attached superiorly along the edge 
of the psoas, to the anterior lamella of the aponeurosis of the transversalis 
muscle, to the ligamentum arcuatum internum, and to the bodies of the 
lumbar vertebrae, leaving arches corresponding with the constricted portions 
of the vertebras for the passage of the lumbar vessels. Lower down it 
passes beneath the external iliac vessels, and is attached along the margin 
of the true pelvis ; externally, it is connected to the crest of the ilium ; 
and, inferiorly, to the outer two-thirds of Poupart's ligament, where it is 
continuous with the fascia transversalis. Passing beneath Poupart's liga- 
ment, it surrounds the psoas and iliacus muscles to their termination, and 
beneath the inner third of the femoral arch forms the posterior segment of 
the sheath of the femoral vessels. » 

The Fascia Pelvica is attached to the inner surface of the os pubis, 
and along the margin of the brim of the pelvis, where it is continuous 
with the iliac fascia. From this extensive origin it descends into the pel- 
vis, and divides into two layers, the pelvic and obturator. 

The pelvic layer ox fascia, when traced from the internal surface of the 
os pubis near the symphysis, is seen to be reflected inwards to the neck 
of the bladder, so as to form the anterior vesical ligaments. Traced 
backwards, it passes between the sacral plexus of nerves and the internal 
iliac vessels, and is attached to the anterior surface of the sacrum ; and 
followed from the sides of the pelvis, it descends to the base of the bladder 
and divides into three layers, one, ascending, is reflected upon the side of 
that viscus, encloses the vesical plexus of veins, and forms the lateral liga- 
ments of the bladder. A middle layer passes inwards between the base 



PERINEAL FASCLE. 



269 



of the bladder and the upper surface of the rectum, and was named by 
Mr. Tyrrell the recto-vesical fascia ; and an inferior layer passes behind 
the rectum, and, with the layer of the opposite side, completely invests 
that intestine. 



Fig. 141 • 




The obturator fascia passes directly downwards from the splitting of 
the layers of the pelvic fascia, and covers in the obturator internus muscle 
and the internal pudic vessels and nerve ; it is attached to the ramus of 
the os pubis and ischium in front, and below to the falciform margin of 
the great sacro-ischiatic ligament. Lying between these two layers of 
fascia is the levator ani muscle, which arises from their angle of separa- 
tion. The levator ani is covered in inferiorly by a third layer of fascia, 
which is given off by the obturator fascia, and is continued downwards 
upon the inferior surface of the muscle to the extremity of the rectum, 
where it is lost. This layer may be named, from its position and inferior 
attachment, the anal fascia. 

Perineal Fascle. — In the perineum there are two fasciae of much im- 
portance, the superficial and deep perineal fascia. 

The superficial perineal fascia is a thin aponeurotic layer, which covers 
in the muscles of the genital portion of the perineum and the root of the 
penis. It is firmly attached at each side to the ramus of the os pubis and 
ischium ; posteriorly it is reflected backwards beneath the transversi perinei 
muscles, to become connected with the deep perineal fascia ; while ante- 
riorly it is continuous with the dartos of the scrotum. 

The deep perineal fascia (Camper's ligament, triangular ligament) is 
situated behind the root of the penis, and is firmly stretched across be- 
tween the ramus of the os pubis and ischium of each side, so as to con- 
stitute a strong septum of defence to the outlet of the pelvis. At its infe- 

* A transverse section of the pelvis, showing the distribution of the pelvic fascia. 
I. The bladder. 2. The vesicula seminalis of one side, divided across. 3. The rectum. 
4. The iliac fascia, covering in the iliacus and psoas muscles (5) ; and forming a sheath 
for the external iliac vessels (6). 7. The anterior crural nerve, excluded from the 
sheath. 8. The pelvic fascia. 9. Its ascending layer, forming the lateral ligament of 
the bladder of one side, and a sheath to the vesical plexus of veins. 10. The recto- 
vesical fascia of Mr. Tyrrell, formed by the middle layer. 11. The inferior layer sur- 
rounding the rectum and meeting at the middle line with the fascia of the opposite side. 
12. The levator ani muscle. 13. The obturator internus muscle, covered in by the ob- 
turator fascia, which also forms a sheath for the internal pudic vessels and nerve (14). 
15. The layer of fascia which invests the under surface of the levator ani muscle, the 
anal fascia. 

23* 



270 



PERINEAL FASCIAE. 



rior border it divides into two layers, one of which is continued forwards, 
and is continuous with the superficial perineal fascia ; while the other is 



Fig. 142 * 




prolonged backwards to the rectum, and, joining with the anal fascia, 
assists in supporting the extremity of that intestine. The deep perineal 
fascia is composed of two layers, which are separated from each other by 
several important parts, and traversed by the membranous portion of the 
urethra. The anterior layer is nearly plane in its direction, and sends a 
sheath forwards around the anterior termination of the membranous ure- 
thra, to be attached to the posterior part of the bulb. The posterior layer 
is oblique, and sends a funnel-shaped process backwards, which invests 

the commencement of the mem- 
s ' T branous urethra and the prostate 

gland. The inferior segment of 
this funnel-shaped process is 
continued backward beneath the 
prostate gland and the vesiculae 
seminales, and is continuous with 
the recto-vesical fasciae of Tyr- 
rell, which is attached poste- 
riorly to the recto-vesical fold 
of peritoneum, and serves the 
important office of retaining that 
duplicative in its proper situa- 
tion. 

* The pubic arch with the attachments of the perineal fasciae. 1, 1, 1. The superfi- 
cial perineal fascia divided by a ^ shaped incision into three flaps ; the lateral flaps 
are turned over the ramus of the os pubis and ischium at each side, to which they are 
firmly attached ; the posterior flap is continuous with the deep perineal fascia. 2. The 
deep perineal fascia. 3. The opening for the passage of the membranous portion of the 
urethra, previously to entering the bulb. 4. Two projections of the anterior layer of the 
deep perineal fascia, corresponding with the position of Cowper's glands. 

t A side view of the viscera of the pelvis, showing the distribution of the perineal 
and pelvic fascia?. I. The symphysis pubis. 2. The bladder. 3. The recto-vesical fold 
of peritoneum, passing from the anterior surface of the rectum to the posterior part of 
tiie bladder ; from the upper part of the fundus of the bladder it is reflected upon the 




FASCIAE OF THE UPPER EXTREMITY. 271 

Between the two layers of the deep perineal fascia are situated, there- 
fore, the whole extent of the membranous portion of the urethra, the com- 
pressor urethras muscle, Cowper's glands, the internal pudic and bulbous' 
arteries, and a plexus of veins. Mr. Tyrrell considers the anterior lamella 
alone as the deep perineal fascia, and the posterior lamella as a distinct 
layer of fascia, covering in a considerable plexus of veins. 

FASCIA OF THE UPPER EXTREMITY. 

The superficial fascia of the upper extremity contains between its layers 
the superficial veins and lymphatics, and the superficial nerves. 

The deep fascia is thin over the deltoid and pectoralis major muscles, 
and in the axillary space, but thick upon the dorsum of the scapula, where 
it binds down the infra-spinatus muscle. It is attached to the clavicle, 
acromion process, and spine of the scapula. In the upper arm it is some- 
what stronger, and is inserted into the condyloid ridges, forming the in- 
termuscular septa. In the fore-arm it is very strong, and at the bend of 
the elbow its thickness is augmented by a broad band, which is given off 
from the inner side of the tendon of the biceps. It is firmly attached to 
the olecranon process, to the ulna, and to the prominent points about the 
wrist. Upon the front of the wrist it is continuous with the anterior annu- 
lar ligament, which is considered by some anatomists to be formed by the 
deep fascia, but which I am more disposed to regard as a ligament of the 
wrist. On the posterior aspect of this joint, it forms a strong transverse 
band, the posterior annular ligament, beneath which the tendons of the 
extensor muscles pass, in distinct sheaths. The attachments of the pos- 
terior annular ligament are, the radius on one side, and the ulna and pisi- 
form bone on the opposite side of the joint. 

The tendons, as they pass beneath the annular ligaments, are surrounded 
by synovial bursas. The dorsum of the hand is invested by a thin fascia, 
which is continuous with the posterior annular ligament. 

The palmar fascia is divided into three portions. A central portion, 
which occupies the middle of the palm, and two lateral portions, which 
spread out over the sides of the hand, and are continuous with the dorsal ' 
fascia. The central portion is strong and tendinous : it is narrow at the 
wrist, where it is attached to the annular ligament, and broad over the 
heads of the metacarpal bones, where it divides into eight slips, which are 
inserted into the sides of the base of the first phalanx of each finger. The 

abdominal parietes. 4. The ureter. 5. The vas deferens crossing the direction of the 
ureter. 6. The vesicula seminalis of the right side. 7, 7. The prostate gland divided 
by a longitudinal section. 8, 8. The section of a ring of elastic tissue encircling the 
prostatic portion of the urethra at its commencement. 9. The prostatic portion of the 
urethra. 10. The membranous portion, enclosed by the compressor urethrge muscle. 
11. The commencement of the corpus spongiosum penis, the bulb. 12. The anterior 
ligaments of the bladder, formed by the reflection of the pelvic fascia, from the internal 
surface of the os pubis to the neck of the bladder. 13. The edge of the pelvic fascia at 
the point where it is reflected upon the rectum. 14. An interval between the pelvic 
fascia and deep perineal fascia, occupied by a plexus of veins. 15. The deep perineal 
fascia; its two layers. 16. Cowper's gland of the right side, situated between the two 
layers below the membranous portion of the urethra. 17. The superficial perineal 
fascia, ascending in front of the root of the penis to become continuous with the dartos 
of the scrotum (18). 19. The layer of the deep fascia which is prolonged to the rectum. 
20. The lower part of the levator ani ; its fibres are concealed by the anal fascia. 21. 
The inferior segment of the funnel-shaped process given off from the posterior layer of 
the deep perineal fascia, which is continuous with the recto-vesical fascia of Tyrrell. 
The attachment of this fascia to the recto-vesical fold of peritoneum is seen at 22. 



272 FASCIiE OF THE LOWER EXTREMITY. 

fascia is strengthened at its point of division into slips, by strong fasciculi 
of transverse fibres, and the arched interval left between the slips gives 
passage to the tendons of the flexor muscles. The arches between the 
lingers transmit the digital vessels and nerve, and lumbricales muscles. 

FASCIiE OF THE LOWER EXTREMITY. 

The superficial fascia contains between its two layers the superficial 
vessels and nerves of the lower extremity. At the groin these two layers 
are separated from each other by the superficial lymphatic glands, and the 
deep layer is attached to Poupart's ligament, while the superficial layer is 
continuous with the superficial fascia of the abdomen. 

The deep fascia of the thigh is named, from its great extent, the fascia 
lata; it is thick and strong upon the outer side of the limb, and thinner 
upon its posterior side. That portion of fascia which invests the gluteus 
maximus is very thin, but that which covers in the gluteus medius is ex- 
cessively thick, and gives origin by its inner surface, to the superficial 
fibres of that muscle. The fascia lata is attached superiorly to Poupart's 
ligament, the crest of the ilium, sacrum, coccyx, tuberosity of the ischium, 
ramus of the ischium, and pubes ; in the thigh it is inserted into the linea 
aspera, and around the knee is connected with the prominent points of 
that joint. It possesses also two muscular attachments, by means of the 
tensor vaginas femoris, which is inserted between its two layers on the 
outer side, and the gluteus maximus, which is attached to it behind. 

In addition to the smaller openings in the fascia lata which transmit the 
small cutaneous vessels and nerves, there exists at the upper and inner 
extremity of the thigh, an oblique foramen, which gives passage to the 
superficial lymphatic vessels, and the large subcutaneous vein of the lower 
extremity, the internal saphenous vein, and is thence named the saphenous 
opening. The existence of this opening has given rise to the division of 
the upper part of the fascia lata into two portions, an iliac portion and a 
pubic portion. 

The iliac portion is situated upon the iliac side of the opening. It is 
attached to the crest of the ilium, and along Poupart's ligament to the 
spine of the os pubis, whence it is reflected downwards and outwards, in 
an arched direction, and forms a falciform border, which constitutes the 
outer boundary of the saphenous opening. The edge of this border im- 
mediately overlies, and is reflected upon the sheath of the femoral vessels, 
and the lower extremity of the curve is continuous with the pubic portion. 

The pubic portion, occupying the pubic side of the saphenous opening, 
is attached to the spine of the os pubis and pectineal line ; and, passing 
outwards behind the sheath of the femoral vessels, divides into two layers ; 
the anterior layer is continuous with that portion of the iliac fascia which 
forms the sheath of the iliacus and psoas muscles, and the posterior layer 
is lost upon the capsule of the hip joint. 

The interval between the falciform border of the iliac portion and the 
opposite surface of the pubic portion is closed by a fibrous layer, which is 
pierced by numerous openings for the passage of lymphatic vessels, and is 
thence named cribriform fascia. The cribriform fascia is connected with 
the sheath of the femoral vessels, and forms one of the coverings of femoral 
hernia. When the iliac portion of the fascia lata is removed from its at- 
tachment to Poupart's ligament and is turned aside, the sheath of the 
femoral vessels (the femoral or crural canal) is brought into view ; and if 



FEMORAL HERNIA. 



273 




Poupart's ligament be carefully 
divided, the sheath may be isolated, 
and its continuation with the trans- 
versalis and iliac fascia clearly de- 
monstrated. In this view the sheath 
of the femoral vessels is an infundi- 
buliform continuation of the abdo- 
minal fascise, closely adherent to the 
vessels a little way down the thigh, 
but much larger than the vessels it 
contains at Poupart's ligament. If 
the sheath be opened, the artery and 
vein will be found lying side by 
side, and occupying the outer two- 
thirds of the sheath, leaving an in- 
fundibuliform interval between the 
vein and the inner wall of the sheath. 
The superior opening of this space 

is named the femoral ring ; it is bounded in front by Poupart's ligament, 
behind by the os pubis, internally by Gimbernat's ligament, and externally 
by the femoral vein. The interval itself serves for the passage of the super- 
ficial lymphatic vessels from the saphenous opening to a lymphatic gland, 
which generally occupies the femoral ring ; and from thence they proceed 
into the current of the deep lymphatics. The femoral ring is closed merely 
by a thin layer of subserous areolar tissue,! "which retains the lymphatic 
gland in its position, and is named septum, crurale ; and by the peritoneum. 
It follows from this description, that the femoral ring must be a weak point 
in the parietes of the abdomen, particularly in the female, where the femoral 
arch, or space included between Poupart's ligament and the border of the 
pelvis, is larger than in the male, while the structures which pass through 
it are smaller. It happens consequently, that, if violent or continued 
pressure be made upon the abdominal viscera, a portion of intestine may 
be forced through the femoral ring into the infundibuliform space in the 
sheath of the femoral vessels, carrying before it the peritoneum and the 
septum crurale, — this constitutes femoral hernia. If the causes which 
give rise to the formation of this hernia continue, the intestine, unable to 
extend further down the sheath, from the close connexion of the latter 
with the vessels, will in the next place be forced forwards through the 
saphenous opening in the fascia lata, carrying before it two additional 
coverings, the sheath of the vessels, or fascia propria, and the cribriform 

* A section of the structures which pass beneath the femoral arch. 1. Poupart's liga- 
ment. 2, 2. The iliac portion of the fascia lata, attached along the margin of the crest 
of the ilium, and along Poupart's ligament, as far as the spine of the os pubis (3). 4, 
The pubic portion of the fascia lata, continuous at 3 with the iliac portion, and passing 
outwards behind the sheath of the femoral vessels to its outer border at 5, where it 
divides into two layers ; one is continuous with the sheath of the psoas (6) and iliacus 
(7) ; the other (8) is lost upon the capsule of the hip joint (9). 10. The crural nerve, 
enclosed in the sheath of the psoas and iliacus. 11. Gimbernat's ligament. 12. The 
femoral ring, within the femoral sheath. 13. The femoral vein. 14. The femoral ar- 
tery ; the two vessels and the ring are surrounded by the femoral sheath, and thin septa 
are sent between the anterior and posterior wall of the sheath, dividing the artery from 
the vein, and the vein from the femoral ring. 

f This areolar tissue is sometimes very considerably thickened by a deposit of fat 
within its areolae, and forms a thick stratum over the hernial sac. 



274 FASCIAE OF THE LEG. 

fascia ; and then curving upwards over Poupart's ligament, the hernia will 
become placed beneath the superficial fascia and integument. 

The direction which femoral hernia takes in its descent is at first down- 
wards, then forwards, and then upwards ; and in endeavouring to reduce 
it, the application of the taxis must have reference to this course, and be 
directed in precisely the reverse order. The coverings of femoral hernia 
are the 

Integument, Fascia propria, 

Superficial fascia, Septum crurale, 

Cribriform fascia, Peritoneal sac. 

The Fascia of the leg is strong in the anterior tibial region, and gives 
origin by its inner surface to the upper part of the tibialis anticus, and ex- 
tensor longus digitorum muscles. 

It is firmly attached to the tibia and fibula at each side, and becomes 
thickened interiorly into a narrow band, the anterior annular ligament, 
beneath which the tendons of the extensor muscles pass into the dorsum 
of the foot, in distinct sheaths lined by synovial bursas. Upon the outer 
side it forms a distinct sheath, which envelopes the peronei muscles, and 
ties them to the fibula. The anterior annular ligament is attached by one 
extremity to the outer side of the os calcis, and divides in front of the 
joint into two bands ; one of which is inserted into the inner malleolus, 
while the other spreads over the inner side of the foot, and becomes con- 
tinuous with the internal portion of the plantar fascia. 

The fascia of the dorsum of the foot is a thin layer given off from the 
low r er border of the anterior annular ligament : it is continuous at each 
side with the lateral portions of the plantar fascia. 

The fascia of the posterior part of the leg is much thinner than the ante- 
rior, and consists of two layers, superficial and deep. The superficial 
layer is continuous with the posterior fascia of the thigh, and is increased 
in thickness upon the outer side of the leg by an expansion derived from 
the tendon of the biceps ; it terminates interiorly in the external and in- 
ternal annular ligaments. The deep layer is stretched across between the 
tibia and fibula, and forms the intermuscular fascia between the superficial 
and deep layer of muscles. It covers in superiorly the popliteus muscle, 
receiving a tendinous expansion from the semi-membranosus muscle, and 
is attached to the oblique line of the tibia. 

The internal annular ligament is a strong fibrous band, attached above 
to the internal malleolus, and below to' the side of the inner tuberosity of 
the os calcis. It is continuous above with the posterior fascia of the leg, 
and below with the plantar fascia, forming sheaths for the passage of the 
flexor tendons and vessels into the sole of the foot. 

The external annular ligament, shorter than the internal, extends from 
the extremity of the outer malleolus to the side of the os calcis, and serves 
to bind down the tendons of the peronei muscles in their passage beneath 
the external ankle. 

The Plantar fascia consists of three portions, a middle and two 
lateral. 

The middle portion is thick and dense, and is composed of strong apo- 
neurotic fibres, closely interwoven with each other. It is attached poste- 
riorly to the inner tuberosity of the os calcis, and terminates under the 
heads of the metatarsal bones in five fasciculi. Each of these fasciculi 



ON THE ARTERIES. 275 

divides into two slips, which are inserted one on each side into the bases 
of the first phalanges of the toes, leaving an interval between them for the 
passage of the flexor tendons. The point of division of this fascia into 
fasciculi and slips, is strengthened by transverse bands, which preserve 
the solidity of the fascia at its broadest part. The intervals between the 
toes give passage to the digital arteries and nerves, and to the lumbricales 
muscles. 

The lateral portions are thin, and cover the sides of the sole of the foot ; 
they are continuous behind with the internal and external annular liga- 
ments ; on the inner side with the middle portion, and externally with the 
dorsal fascia. 

Besides constituting a strong layer of investment and defence to the soft 
parts situated in the sole of the foot, these three portions of fascia send 
processes inwards, which form sheaths for the different muscles. A strong 
septum is given off from each side of the middle portion of the plantar 
fascia, which is attached to the tarsal bones, and divides the muscles into 
three groups, a middle and two lateral; and transverse septa are stretched 
between these to separate the layers. The superficial layer of muscles 
derive a part of their origin from the plantar fascia. 



CHAPTER VI. 

ON THE ARTERIES. 



The arteries are the cylindrical tubes which convey the blood from the 
ventricles of the heart to every part of the body. They are dense in struc- 
ture, and preserve for the most part the cylindrical form when emptied of 
their blood, which is their condition after death: hence they were con- 
sidered by the ancients as the vessels for the transmission of the vital 
spirits,* and were therefore named arteries (a^ r^slv, to contain air). 

The artery proceeding from the left ventrical of the heart contains the 
pure or arterial blood, which is distributed throughout the entire system, 
and constitutes, with its returning veins, the greater or systemic circula- 
tion. That which emanates from the right ventricle, conveys the impure 
blood to the lungs; and, with its corresponding veins, establishes the 
lesser or pulmonary circulation. 

The whole of the arteries of the systemic circulation proceed from a 
single trunk, named the aorta, from which they are given off as branches, 
and divide and subdivide to their ultimate ramifications, constituting the 
great arterial tree which pervades, by its minute subdivisions, every part 
of the animal frame. The mode in which the division into branches takes 
place, is deserving of remark. From the aorta, the branches, for the most 
part, pass off at right angles, as if for the purpose of checking the impetus 
with which the blood would otherwise rush along their cylinders from the 
main trunk ; but in the limbs a very different arrangement is adopted ; 
the branches are given off from the principal artery at an acute angle, so 

* To Galen is due the honour of having discovered that arteries contained blood, and 
not air. 



276 GENERAL ANATOMY OF ARTERIES. 

that no impediment may be offered to the free circulation of the vital fluid. 
The division of arteries is usually dichotomous, as of the aorta into the 
two common iliacs, common carotid into the external and internal, &c. ; 
but in some few instances a short trunk divides suddenly into several 
branches, which proceed in different directions ; this mode of division is 
termed an axis, as the thyroid and coeliac axis. 

In the division of an artery into two branches, it is observed that the 
combined areae of the two branches are somewhat greater than that of the 
single trunk ; and if the combined areae of all the branches at the peri- 
phery of the body were compared with that of the aorta, it would be seen 
that the blood, in passing from the aorta into the numerous distributing 
branches, was flowing through a conical space, of which the apex might 
be represented by the aorta, and the base by the surface of the body. 
The advantage of this important principle in facilitating the circulation is 
sufficiently obvious ; for the increased channel which is thus provided for 
the current of the blood, serves to compensate for the retarding influence 
of friction, resulting from the distance of the heart and the division of the 
vessels. 

Communications between arteries are very free and numerous, and in- 
crease in frequency with the diminution in size of the branches ; so that, 
through the medium of the minute ramifications, the entire body may be 
considered as one uninterrupted circle of inosculations, or anastomoses 
(dva between, rfTojxa mouth). This increase in the frequency of anastomosis 
in the smaller branches is a provision for counteracting the greater liability 
to impediment existing in them than in the larger branches. Where free- 
dom of circulation is of vital importance, this communication of the arteries 
is very remarkable, as in the circle of Willis in the cranium, or in the dis- 
tribution of the arteries of the heart. It is also strikingly seen in situations 
where obstruction is most likely to occur, as in the distribution to the ali- 
mentary canal, around joints, or in the hand and foot. Upon this free 
communication existing everywhere between arterial branches is founded 
the principle of cure in the ligature of large arteries ; the ramifications of 
the branches given off from the artery above the ligature inosculate with 
those which proceed from the trunk of the vessel below the ligature ; these 
anastomosing branches enlarge and constitute a collateral circulation, in 
which, as is shown in the beautifiul preparations made by Sir Astley 
Cooper, several large branches perform the office of the single obliterated 
trunk.* 

The arteries do not terminate directly in veins ; but in an intermediate 
system of vessels, which, from their minute size (about g^o of" an inch in 
diameter), are termed capillaries (capillus, a hair). The capillaries con- 
stitute a microscopic network, which is distributed through every part oi 
the body, so as to render it impossible to introduce the smallest needle 
point beneath the skin without wounding several of these fine vessels. It 
is through the medium of the capillaries, that all the phenomena of nutri- 
tion and secretion are performed. They are remarkable for their unifor- 
mity of diameter, and for the constant divisions and communications 
which take place between them, without any alteration of size. They 

* I have a preparation, showing the collateral circulation in a dog, in which I tied 
the abdominal aorta ; the animal died from over-feeding nearly two years after the 
operation. 



STRUCTURE OF ARTERIES. 277 

inosculate on the one hand with the terminal ramusculi of the arteries ; 
and on the other with the minute radicles of the veins. 

Arteries are composed of three coats, external, middle, and internal. 
The external or areolo-fibrous coat is firm and strong, and serves at the 
same time as the chief means of resistance of the vessel, and of connection 
to surrounding parts. It consists of condensed areolo-fibrous tissue, 
strengthened by an interlacement of glistening fibres which are partly 
longitudinal and partly encircle the cylinder of the tube in an oblique 
direction. Upon the surface the areolar tissue is loose, to permit of the 
movements of the artery in distention and contraction. 

The middle coat is that upon which the thickness of the artery depends ; 
it is yellowish in colour, and so brittle as to be cut through by the thread 
in the ligature of a vessel.* 

The internal coat is a thin serous membrane which lines the interior of 
the artery, and gives it the smooth polish which that surface presents. It 
is continuous with the lining membrane of the heart, and through the me- 
dium of the capillaries with that of the venous system. 

In intimate structure an artery is more complicated than the above de- 
scription would imply. The internal coat, for example, is composed of 
two layers, and the middle of three, so that, with the external coat, there 
are six layers entering into the composition of an artery. The innermost 
coat is a tesselated epithelium analogous to that of other serous membranes. 
The second coat from within is a thin, rigid membrane, pierced with a 
number of round or oval-shaped holes, and supporting a thin layer of flat, 
longitudinal fibres. From these characters it has been denominated the 
fenestrated or striated coat. The third layer, which is the innermost part 
of the middle coat, is composed of flat, longitudinal fibres, analogous to 
those of organic muscle. The fourth layer, the thickest of the whole, is 
composed of muscular fibres of organic life, arranged in a circular direc- 
tion around the vessel. The fifth, or outermost part of the middle coat, 
is a thin layer of elastic tissue ; this is present only in the large arteries. 
The sixth is the external or areolo-fibrous coat. 

The arteries in their distribution through the body are included in a 
loose areolar investment which separates them from surrounding tissues, 
and is called a sheath. Around the principal vessels the sheath is an im- 
, portant structure ; it is composed of areolo-fibrous tissue, intermingled 
with tendinous fibres, and is continuous with the fasciae of the region in 
which the arteries are situated, as with the thoracic and cervical fasciae in 
the neck, transversalis and iliac fasciae, and fascia lata in the thigh, &c. 
The sheath of the arteries contains also their accompanying veins, and 
sometimes a nerve. 

The coats of arteries are supplied with blood like other organs of the 
body, and the vessels which are distributed to them are named vasa vaso- 
rum. They are also provided with nerves ; but the mode of distribution 
of the nerves is at present unknown. 

In the consideration of the arteries, we shall first describe the aorta, and 

Tlie second or middle coat of the arteries has given rise to no little discussion among 
the continental anatomists. It will be found, however, to consist of fibres, flat, elastic, 
for the most part transverse, and belonging to the yellow elastic tissue. Some of the 
fibres are longitudinal, and some of the transverse present strong evidences of belonging 
to the muscular system of organic life ; so that the coat may, 1 think, be fairly staled to 
be a mixed one, composed of yellow, elastic, and organic muscular fibres. It is best 
studied in the aorta or some large trunk. — G. 

24 



278 AORTA. 

the branches of that trunk with their subdivisions, which together consti- 
tute the efferent portion of the systemic circulation ; and then the pul- 
monary artery as the efferent trunk of the pulmonary circulation. 

Fig. 145.* 




| AORTA. 

The aorta arises from the left ventricle, at the middle of the root of the 
heart, and opposite the articulation of the fourth costal cartilage with the 
sternum. At its commencement it presents three dilatations, called the 
sinus aortici, which correspond with the three semilunar valves. It as- 
cends at first to the right, then curves backwards and to the left, and de- 
scends on the left side of the vertebral column to the fourth lumbar verte- 
bra. Hence it is divided into — ascending — arch — and descending aorta. 

* The large vessels which proceed from the root of the heart, with their relations ; 
the heart has been removed. 1. The ascending aorta. 2. The arch. 3. The thoracic 
portion of the descending aorta. 4. The arteria innominata, dividing into, 5, the right 
carotid, which again divides at 6, into the external and internal carotid ; and 7, the 
right subclavian artery. 8. The axillary artery; its extent is designated by a dotted 
line. 9. The brachial artery. 10. The right pneumogastric nerve running by the side 
of the common carotid, in front of the right subclavi-an artery, and behind the root of 
the right lung. 11. The left common carotid, having to its outer side the left pneumo- 
gastric nerve, which crosses the arch of the aorta, and as it reaches its lower border is 
seen to give oft' the left recurrent nerve. 12. The left subclavian artery becoming axil- 
lary and brachial in its course, like the artery of the opposite side. 13. The trunk of 
the pulmonary artery connected to the concavity of the arch of the aorta by a fibrous 
cord, the remains of the ductus arteriosus. 14. The left pulmonary artery. 15. The 
right pulmonary artery. 16. The trachea. 17. The right bronchus. 18. The left 
bronchus. 19, 19. The pulmonary veins. 17, 15, and 19, on the right side, and 14, 18, 
and 19, on the left, constitute the roots of the corresponding lungs, and the relative posi- 
tion of these vessels is preserved. 20. Bronchial arteries. 21, 21. Intercostal arteries; 
the branches from the front of the aorta above and below the number 3 are pericardiac 
and oesophageal branches. 



ARCH OF THE AORTA. 



279 



Relations. — The ascending aorta has in relation with it, in front, the 
trunk of the pulmonary artery, thoracic fascia, and pericardium ; behind, 
the rio-ht pulmonary veins and artery ; to the right side, the right auricle 
and superior cava ; and to the left, the left auricle and the trunk of the 
pulmonary artery. 

Plan of the Relations of the Ascending Aorta, 

In Front. 

Pericardium, 
Thoracic fascia, 
Pulmonary artery. 



Right Side. 

Superior cava, 
Right auricle. 



Ascending Aorta. 



Left Side. 

Pulmonary artery. 
Left auricle. 



Behind. 
Right pulmonary artery, 
Right pulmonary veins. 

Arch. — The upper border of the arch of the aorta is parallel with the 
upper border of the second stemo-costal articulation of the right side in 
front, and the second dorsal vertebra behind, and terminates opposite the 
lower border of the third. 

The anterior surface of the arch is crossed by the left pneumogastric 
nerve, and by the cardiac branches of that nerve and of the sympathetic. 
The posterior surface of the arch is in relation with the bifurcation of the 
trachea and great cardiac plexus, the cardiac nerves, left recurrent nerve, 
and the thoracic duct. The superior border gives off the three great arte- 
ries, viz. the innominata, left carotid, and left subclavian. The inferior 
border, or concavity of the arch, is in relation with the remains of the 
ductus arteriosus, the cardiac ganglion and left recurrent nerve, and has 
passing beneath it the right pulmonary artery and left bronchus. 

Plan of the Relations of the Arch of the Aorta. 

Above. » 

Arteria innominata, 
Left carotid, 
Left subclavian. - 



In Front. 

Left pneumogastric 

nerve, 
Cardiac nerves. 




Behind. 
Bifurcation of the trachea, 
Great cardiac plexus, 
Cardiac nerves, 
Left recurrent nerve, 
Thoracic duct. 



Below. 
Cardiac ganglion, 
Remains of ductus arteriosus, 
Left, recurrent nerve, 
Right pulmonary artery, 
Left bronchus. 



The descending aorta is subdivided in correspondence with the two 
great cavities of the trunk, into the thoracic and abdominal aorta. 



280 



ABDOMINAL AORTA. 



The Thoracic aorta is situated to the left side of the vertebral column, 
but approaches the middle line as it descends, and at the aortic opening 
of the diaphragm is altogether in front of the column. After entering the 
abdomen it again falls back to the left side. 

Relations. — It is in relation, behind, with the vertebral column and 
lesser vena azygos ; in front, with the oesophagus and right pneumogastric 
nerve ; to the left side, with the pleura ; and to the right, with the thoracic 
duct. 

Plan of the Relations of the Thoracic Aorta. 

In Front. 

(Esophagus, 

Right pneumogastric nerve. 



Right Side. 
Thoracic duct. 



Thoracic Aorta. 



Left Side. 
Pleura. 



Behind. 

Lesser vena azygos, 
Vertebral column. 

The Abdominal aorta enters the abdomen through the aortic opening 
of the diaphragm, and descends, lying rather to the left side of the verte- 
bral column, to the fourth lumbar vertebra, where it divides into the two 
common iliac arteries. 

Relations. — It is crossed in front, by the left renal vein, pancreas, trans- 
verse duodenum, and mesentery, and is embraced by the aortic plexus ; 
behind it is in relation with the thoracic duct, receptaculum chyli, and left 
lumbar veins. 

On its left side is the left semilunar ganglion and sympathetic nerve ; 
and on the right, the vena cava, right semilunar ganglion, and the com- 
mencement of the vena azygos. 

Plan of the Relations of the Abdominal Aorta. 

In Front. 

Left renal vein, 

Pancreas, 

Transverse duodenum, 

Mesentery, 

Aortic plexus. 



Right Side. 
Vena cava, 
Right semilunar gan- 
glion, 
Vena azygos. 



Abdominal Aorta. 



Behind. 

Thoracic duct, 
Receptaculum chyli, 
Left lumbar veins. 



Left Side. 

Left semilunar gan- 
glion, 
Sympathetic nerve. 



ARTERIA INNOMINATA. 



281 



Branches.— The branches of the aorta, arranged into a tabular form, 
are, — 
Ascending aorta . . 

Arch of the aorta . . 
Thoracic aorta . . 



Right carotid, 
Right subclavian. 



Abdominal aorta 



Coronary. 

Arteria innominata, 
Left carotid, 
Left subclavian. 
Pericardiac, 
Bronchial, 
(Esophageal, 
Intercostal. 
' Phrenic, 

C Gastric, 
Ccelic axis, < Hepatic, 

( Splenic. 
Supra-renal, 
Renal, 

Superior mesenteric, 
Spermatic, 
Inferior mesenteric, 
Lumbar, 
Sacramedia, 
Common iliacs. 

The Coronary arteries arise from the aortic sinuses at the commence- 
ment of the ascending aorta, immediately above the free margin 01 the 
semilunar valves. The left or anterior coronary, passes forwards, be- 
tween the pulmonary artery and left appendix auricula?, and divides into 
two branches ; one of which winds around the base of the left ventricle in 
the auriculo-ventricular groove, and inosculates with the right coronary, 
forming an arterial circle around the base of the heart ; while the other 
passes along the line of union of the two ventricles, upon the anterior as- 
pect of the heart, to its apex, where it anastomoses with the descending 
branch of the right coronary. It supplies the left auricle and the anterior 
surface of both ventricles. 

The right, or posterior coronary, passes forwards, between the root of 
the pulmonary artery and the right auricle, and winds along the auriculo- 
ventricular groove, to the posterior median furrow, where it descends upon 
the posterior aspect of the heart to its apex, and inosculates with the left 
coronary. It is distributed to the right auricle, and to the posterior surface 
of both ventricles, and sends a large branch along the sharp margin of the 
right ventricle to the apex of the heart. 

ARTERIA INNOMINATA. 

The Arteria innominata (fig. 145, No. 4) is the first artery given ofFby 
the arch of the aorta. It is an inch and a half in length, and ascends 
obliquely towards the right sterno-clavicular articulation, where it divides 
into the right carotid and right subclavian artery. 

Relations. — It is in relation, in front, with the left vena innominata, the 
thymus gland, and the origins of the stemo-thyroid and sterno-hyoid mus- 
cles, which separate it from the sternum. Behind, with the trachea, pneu- 
24* 



282 COMMON CAROTID ARTERIES. 

mogastric nerve and cardiac nerves ,* externally , with the right vena inno- 
minata and pleura ; and internally, with the origin of the left carotid. 

Plan of the Relations of the Arteria Innominata. 

In Front. 
Left vena innominata, 
Thymus gland, 
Sternothyroid, 
Sternohyoid. 



Right Side. 
Right vena innominata, 
Pleura. 



Arteria innominata. 



Left Side. 
Left carotid. 



Behind. 
Trachea, 

Pneumogastric nerve, 
Cardiac nerves. 

The arteria innominata occasionally gives off a small branch, which 
ascends along the middle of the trachea to the thyroid gland. This branch 
was described by Neubauer, and Dr. Harrison names it the middle thyroid 
artery. A knowledge of its existence is important in performing the ope- 
ration of tracheotomy. 

COMMON CAROTID ARTERIES. 

The common carotid arteries (xa^a, the head,) arise, the right from the 
bifurcation of the arteria innominata opposite the right sterno-clavicular 
articulation, the left from the arch of the aorta. It follows, therefore, that 
the right carotid is shorter than the left ; it is also more anterior; and, in 
consequence of proceeding from a branch instead of from the main trunk, 
it is larger than its fellow. 

The Right common carotid artery (fig. 145, No. 5) ascends the neck 
perpendicularly, from the right sterno-clavicular articulation to a level with 
the upper border of the thyroid cartilage, where it divides into the external 
and internal carotid. 

The Left common carotid (fig. 145, No. 11) passes somewhat obliquely 
outwards from the arch of the aorta to the side of the neck, and thence 
upwards to a level with the upper border of the thyroid cartilage, where it 
divides like the right common carotid into the external and internal carotid. 

Relations. — The right common carotid rests, first, upon the longus, colli 
muscle, then upon the rectus anticus major, the sympathetic nerve being 
interposed. The inferior thyroid artery and recurrent laryngeal nerve 
pass behind it at its lower part. To its inner side is the trachea, recurrent 
laryngeal nerve, and larynx ; to its outer side, and enclosed in the same 
sheath, the jugular vein and pneumogastric nerve ; and in front, the sterno- 
thyroid, stemo-hyoid, sterno-mastoid, omo-hyoid, and platysma muscles, 
and the descendens noni nerve. The left common carotid, in addition to 
the relations just enumerated, which are common to both, is crossed near 
its commencement by the left vena innominata ; it lies upon the trachea ; 
then gets to its side, and is in relation with the oesophagus and thoracic 
duct : to facilitate the study of these relations, I have arranged them in a 
tabular form. 



EXTERNAL CAROTID ARTERY. 



283 



Plan of Relations of the Common Carotid Artery. 

In Front. 

Platysma, 

Descendens noni nerve, 

Omohyoid, 

Sterno-mastoid, 

Sternohyoid, 

Stemo-thyroid. 



Externally. 

Internal jugular vein, 
Pneumogastric nerve. 



Common Carotid Artery. 



Internally. 
Trachea, 
Larynx, 
Recurrent laryngeal nerve, 



Behind. 

Longus colli, 
Rectus amicus major, 
Sympathetic, ■ , 

Inferior thyroid artery, 
Recurrent laryngeal nerve. 

Additional Relations of the Left Common Carotid. 

In Front. Behind. Internally. Externally 

Left vena innominata. Trachea, Arteria innominata, Pleura. 

Thoracic duct. OZsophagus. 



EXTERNAL CAROTID ARTERY. 

The External carotid artery ascends nearly perpendicularly from oppo- 
site the upper border of the thyroid cartilage, to the space between the 
neck of the lower jaw and the meatus auditorius, where it divides into the 
temporal and internal maxillary artery. 

Relations. — In front it is crossed by the posterior belly of the digas- 
tricus, stylo-hyoideus, and platysma myoides muscles ; by the hypoglossal 
nerve near its origin ; higher up it is situated in the substance of the 
parotid gland, and is crossed by the facial nerve. Behind, it is separated 
from the internal carotid by the stylo-pharyngeus and stylo-glossus 
muscles, glosso-pharyngeal nerve, and part of the parotid gland. 

Plan of the Relations of the External Carotid Artery. 

In Front. 
Platysma, 
Digastricus, 
Stylo-hyoid, 
Hypoglossal nerve, 
Facial nerve, 
Parotid gland. 



External Carotid Artery. 



Behind. 

Stylo-pharyngeus, 
Stylo-glossus, 
Glosso-pharyngeal nerve, 
Parotid gland. 



284 



SUPERIOR THYROID ARTERY. 



Branches. — The branches of the external carotid are eleven in number, 
and may be arranged into four groups, viz. 

Anterior. Posterior. 

1. Superior thyroid, 4. Mastoid, 

2. Lingual, 5. Occipital, 

3. Facial. 6. Posterior auricular. 



Superior. 

7. Ascending pharyngeal, 

8. Parotidean, 

9. Transverse facial. 



Terminal. 

10. Temporal, 

11. Internal maxillary. 



The anterior branches arise from the commencement of the external 
carotid, within a short distance of each other. The lingual and facial 
bifurcate, not unfrequently, from a common trunk. 

1. The Superior thyroid artery (the first of the branches of the ex- 
ternal carotid) curves downwards to the thyroid gland to which it is dis- 
tributed, anastomosing with its fellow of the opposite side, and with the 
inferior thyroid arteries. In its course it passes beneath the omo-hyoid, 
stemo-thyroid, and sterno-hyoid muscles. 

Fig. 146.* 




Branches. — Hyoid, 

Superior laryngeal, 
Inferior laryngeal, 
Muscular. 

* The carotid arteries, with the branches of the external carotid. 1. The common 
carotid. 2. The external oarotid. 3. The internal carotid. 4. The carotid foramen in 
the petrous portion of the temporal bone. 5. The superior thyroid artery G The lin 
pual artery. 7. The facial artery. 8. The mastoid artery. 9. The occipital 
posterior auricular. 11. The transverse facial artery. 12. " 
13. The temporal. 14. The ascending pharyngeal artery. 



10. The 
The internal maxillary 



LINGUAL AND FACIAL ARTERIES. 285 

The Hyoid branch passes forwards beneath the thyro-hyoideus, and is 
distributed to the depressor muscles of the os hyoides near their insertion. 

The Superior laryngeal pierces the thyro-hyoidean membrane, in com- 
pany with the superior laryngeal nerve, and supplies the mucous mem- 
brane and muscles of the larynx, sending a branch upwards to the 
epiglottis. 

The Inferior laryngeal is a small branch which crosses the crico-thyroi- 
dean membrane along the lower border of the thyroid cartilage. It sends 
branches through the membrane, to supply the mucous lining of the larynx, 
and inosculates with its fellow of the opposite side. 

The Muscular branches are distributed to the depressor muscles of the 
os hyoides and larynx. One of these branches crosses the sheath of the 
common carotid to the under surface of the sterno-mastoid muscle. 

2. The Lingual artery ascends obliquely from its origin, it then 
passes forwards parallel with the great cornu of the os hyoides ; thirdly, it 
ascends to the under surface of the tongue ; and, fourthly, runs forward 
in a serpentine direction to its tip (under the name of the ranine artery), 
where it terminates by inosculating with its fellow of the opposite side. 

Relations. — The Jirst part of its course rests upon the middle constrictor 
muscle of the pharynx, being covered in by the tendon of the digastricus 
and the stylo-hyoid muscle ; the second is situated between the middle 
constrictor and hyo-glossus muscle, the latter separating it from the hypo- 
glossal nerve ; in the third part of its course it lies between the hyo-glossus 
and genio -hyo-glossus; and in the fourth (ranine) rests upon the lingualis 
to the tip of the tongue. 

Branches. — Hyoid, 

Dorsalis linguae, 
Sublingual. 

The Hyoid branch runs along the upper border of the os hyoides, and 
is distributed to the elevator muscles of the os hyoides near their origin, 
inosculating with its fellow of the opposite side. 

The Dorsalis lingua ascends along the posterior border of the hyo- 
glossus muscle to the dorsum of the tongue, and is distributed to the 
tongue, the fauces, and epiglottis, anastomosing with its fellow of the op- 
posite side. 

The Sublingual branch, sometimes considered as a branch of bifurca- 
tion of the lingual, runs along the anterior border of the hyo-glossus, and 
is distributed to the sublingual gland and to the muscles of the tongue. 
It is situated between the mylo-hyoideus and genio-hyo-glossus, generally 
accompanies Wharton's duct for a part of its course, and sends a branch 
to the fraenum linguae. It is the latter branch which affords the consider- 
able haemorrhage which sometimes follows the operation of snipping the 
fraenum in children. 

3. Facial artery. — The Facial artery arises a little above the great 
cornu of the os hyoides, and descends obliquely to the submaxillary gland, 
in which it lies embedded. It then curves around the body of the lower 
jaw, close to the anterior inferior angle of the masseter muscle, ascends 
to the angle of the mouth, and thence to the angle of the eye, where it is 
named the angular artery. The facial artery is tortuous in its course 



286 FACIAL ARTERY. 

over the buccinator muscle, to accommodate itself to the movements of 
the jaws. 

Relations. — Below the jaw it passes beneath the digastricus and stylo- 
hyoid muscles ; on the body of the lower jaw it is covered by the platysma 
myoides, and at the angle of the mouth by the depressor anguli oris and 
zygomatic muscles. It rests upon the submaxillary gland, the lower jaw, 
buccinator, orbicularis oris, levator anguli oris, levator labii superioris 
proprius, and levator labii superioris alaque nasi. 

Its brandies are divided into those which are given off below the jaw 
and those on the face : they may be thus arranged : — 

Below the Jaw. — Inferior palatine, 
Submaxillary, 
Submental, 
Pterygoid. 

On the Face. — Masseteric, 

Inferior labial, 
Inferior coronary, 
Superior coronary, 
Lateralis nasi. 

The Inferior palatine branch ascends between the stylo-glossus and 
stylo-pharyngeus muscles, to be distributed to the tonsil and soft palate, 
and anastomoses with the posterior palatine branch of the internal maxil- 
lary artery. 

The Submaxillary are four or five branches which supply the submaxil- 
lary gland. 

The Submental branch runs forwards upon the mylo-hyoid muscle, under 
cover of the body of the lower jaw, and anastomoses with branches of the 
sublingual and inferior dental artery. 

The Pterygoid branch is distributed to the internal pterygoid muscle. 

The Masseteric branches are distributed to the masseter and buccinator 
muscles. 

The Inferior labial branch is distributed to the muscles and integument 
of the lower lip. 

The Inferior coronary runs along the edge of the lower lip, between the 
mucous membrane and the orbicularis oris ; it inosculates with the cor- 
responding artery of the opposite side. 

The Superior coronary follows the same course along the upper lip, in- 
osculating with the opposite superior coronary artery, and at the middle 
of the lip it sends a branch upwards, to supply the septum of the nose and 
the mucous membrane. 

The Lateralis nasi is distributed to the ala and septum of the nose. 

The Inosculations of the facial artery are very numerous : thus, it anas- 
tomoses with the sublingual branch of the lingual, with the ascending 
pharyngeal and posterior palatine arteries, with the inferior dental as it es- 
capes from the mental foramen, infra-orbital at the infra-orbital foramen, 
transverse facial on the side of the face, and at the angle of the eye with 
the nasal and frontal branches of the ophthalmic artery. 

The facial artery is subject to considerable variety in its extent : it not 
unfrequently terminates at the angle of the nose or mouth, and is rarely 
symmetrical on both sides of the face. 



TRANSVERSALIS FACIEI. 287 

4. The Mastoid artery turns downwards from its origin, to be dis- 
tributed to the sterno-mastoid muscle, and to the lymphatic glands of the 
neck ; sometimes it is replaced by two small branches. 

5. The Occipital artery, smaller than the anterior branches, passes 
backwards beneath the posterior belly of the digastricus, the trachelo- 
mastoid and sterno-mastoid muscles, to the occipital groove in the mastoid 
portion of the temporal bone. It then ascends between the splenius and 
complexus muscles, and divides into two branches which are distributed 
upon the occiput, anastomosing with the opposite occipital, the posterior 
auricular, and temporal artery. The hypoglossal nerve curves around this 
artery near its origin from the external carotid. 

Branches. — It gives off only two branches deserving of name, the infe- 
rior meningeal and princeps cervicis. 

The Inferior meningeal ascends by the side of the internal jugular vein, 
and passes through the foramen lacerum posterius, to be distributed to 
the dura mater. 

The Arteria 'princess cervicis is a large and irregular branch. It de- 
scends the neck between the complexus and semi-spinalis colli, and inos- 
culates with the profunda cervicis of the subclavian. This branch is the 
means of establishing a very important collateral circulation between the 
branches of the carotid and subclavian, after the ligature of the common 
carotid artery. 

6. The Posterior auricular artery arises from the external carotid, 
above the level of the digastric and stylo-hyoid muscles, and ascends be- 
neath the lower border of the parotid gland, and behind the concha, to be 
distributed by two branches to the external ear and side of the head, anas- 
tomosing with the occipital and temporal arteries ; some of its branches 
pass through fissures in the fibro-cartilage, to be distributed to the anterior 
surface of the pinna. The anterior auricular arteries are branches of the 
temporal. 

Branches. — The posterior auricular gives off but one named branch, the 
stylo-mastoid , which enters the stylo-mastoid foramen to be distributed to 
the aquaeductus Fallopii and tympanum. 

7. The Ascending pharyngeal artery, the smallest of the branches 
of the external carotid, arises from that trunk near its bifurcation, and as- 
cends between the internal carotid and the side of the pharynx to the base 
of the skull, where it divides into two branches ; meningeal, which enters 
the foramen lacerum posterius, to be distributed to the dura mater ; and 
pharyngeal. It supplies the pharynx, tonsils, and Eustachian tube. 

8. The Parotidean arteries are four or five large branches which are 
given off from the external carotid whilst that vessel is situated in the pa- 
rotid gland. They are distributed to the structure of the gland, their ter- 
minal branches reaching the integument and the side of the face. 

9. The Transversalis Faciei arises from the external carotid, whilst 
that trunk is lodged within the parotid gland ; it crosses the massetei 
muscle, lying parallel with and a little above Stenon's duct ; and is dis- 
tributed to the temporo-maxillary articulation, and to the muscles and hv 



288 INTERNAL MAXILLARY ARTERY. 

tegument of the side of the face, inosculating with the infra-orbital and 
facial artery. This artery is not unfrequently a branch of the temporal. 

10. The Temporal artery is one of the two terminal branches of the 
external carotid. It ascends over the root of the zygoma ; and, at about 
an inch and a half above the zygomatic arch ? divides into an anterior and 
a posterior temporal branch. The anterior temporal is distributed over 
the front of the temple and arch of the skull, and anastomoses with the 
opposite anterior temporal, and with the supra-orbital and frontal artery. 
The posterior temporal curves upwards and backwards, and inosculates 
with its fellow of the opposite side, with the posterior auricular and occi- 
pital artery. 

The trunk of the temporal artery is covered in by the parotid gland and 
by the attrahens aurem muscle, and rests on the temporal fascia. 

Branches. — Orbitar, 

Anterior auricular, 
Middle temporal. 
The Orbitar artery is a small branch, not always present, which passes 
forward immediately above the zygoma, between the two layers of the 
temporal fascia, and inosculates beneath the orbicularis palpebrarum with 
the palpebral arteries. 

The Anterior auricular arteries are distributed to the anterior portion 
of the pinna. 

The Middle temporal branch passes through an opening in the temporal 
fascia immediately above the zygoma, and supplies the temporal muscle 
inosculating with the deep temporal arteries. 

11. The Internal maxillary artery, the other terminal branch of the 
external carotid, has next to be examined. 

Dissection. — The Internal maxillary artery passes inwards behind the 
neck of the lower jaw to the deep structures in the face ; we require, 
therefore, to remove several parts for the purpose of seeing it completely. 
To obtain a good view of the vessel, the zygoma should be sawn across 
in front of the external ear, and the malar bone near the orbit. Turn 
down the zygomatic arch with the masseter muscle. In doing this, a 
small artery and nerve will be seen crossing the sigmoid notch of the 
lower jaw, and entering the masseter muscle (the masseteric). Cut away 
the tendon of the temporal muscle from its insertion into the coronoid 
process, and turn it upwards towards its origin ; Some vessels will be seen 
entering its under surface ; these are the deep temporal. Then saw the 
ramus of the jaw across its middle, and dislocate it from its articulation 
with the temporal bone. Be careful in doing this to carry the blade of 
the knife close to the bone, lest any branches of nerves should be injured. 
Next raise this portion of bone, and with it the external pterygoid muscle. 
The artery, together with the deep branches of the inferior maxillary nerve, 
will be seen lying on the pterygoid muscles. These are to be carefully 
freed from fat and areolar tissue, and then examined. 

This artery commences in the substance of the parotid gland, opposite 
the meatus auditorius externus ; it passes in the first instance horizontally 
forward behind the neck of the lower jaw ; next, curves around the lowei 
border of the external pterygoid muscle near its origin, and ascends ob- 
liqnely forwards upon the outer side of that muscle ; it then passes between 



INTERNAL MAXILLARY ARTERY. 



289 



Fig. 147.* 



.15 



the two heads of the external pterygoid, 
and enters the pterygo-maxillary fossa. 
Occasionally it passes between the two 
pterygoid muscles, without appearing on 
the outer surface of the external ptery- 
goid. In consideration of its course, 
this artery may be divided into three 
portions: maxillary, pterygoid, and 
spheno-maxillary. 

Relations. — The maxillary portion is 
situated between the ramus of the jaw 
and the internal lateral ligament, lying 
parallel with the auricular nerve ; the 
pterygoid portion between the external 
pterygoid muscle, and the masseter and 

temporal muscle. The pterygo-maxillary portion lies between the two 
heads of the external pterygoid muscle, and, in the spheno-maxillary fossa, 
is in relation with Meckel's ganglion. 

Branches. 
Maxillary Portion. 

Tympanic, 
Inferior dental, 
Arteria meningea media, 
Arteria meningea parva. 




Pterygoid Portion. 
Deep temporal branches, 
External pterygoid, 
Internal pterygoid, 
Masseteric, 
Buccal. 



Pterygo-maxillary Portion. 
Superior dental, 
Infra- orbital, 
Pterygo-palatine, 
Spheno-palatine, 
Posterior palatine, 
Vidian. 

The Tympanic branch is small, and not likely to be seen in an ordinary 
dissection ; it is distributed to the temporo-maxillary articulation and 
meatus, and passes into the tympanum through the flssura Glaseri. 

The Inferior dental descends to the dental foramen, and enters the 
canal of the lower jaw in company with the dental nerve. Opposite the 
bicuspid teeth it divides into two branches, one of which is continued on- 
wards within the bone as far as the symphisis, to supply the incisor teeth, 

* 1. The external carotid artery. 2. The trunk of the transverse facial artery. 3, 4. 
The two terminal branches of the external carotid. 3. The temporal artery; and 4. 
The internal maxillary, the first or maxillary portion of its course; the limit of this por- 
tion is marked by an arrow. 5. The second, or pterygoid portion, of the artery ; the 
limits are bounded by the arrows. 6. The third or pterygo-maxillary portion. The 
branches of the maxillary portion are, 7. A tympanic branch. 8. The arteria meningea 
magna. 9. The arteria meningea parva. 10. The inferior dental artery. The branches 
of the second portion are wholly muscular, the ascending ones being distributed to the 
temporal, and the descending to the four other muscles of the inter-maxillary region, 
viz. the two pterygoids, the masseter and buccinator. The branches of the pterygo- 
maxillary portion of the artery are, 1 1. The superior dental artery. 12. The infra-or- 
bital artery. 13. The posterior palatine. 14. The spheno-palatine or nasal. 15. The 
pterygo-palatine. 16. The Vidian. * The remarkable bend which the third portico 
of the artery makes as it turns inwards to enter the pterygo-maxillary fossa. 

25 t 



290 INTERNAL MAXILLARY ARTERY. 

while the other escapes with the nerve at the mental foramen, and anasto- 
moses with the inferior labial and submental branch of the facial. It sup- 
plies the teeth of the lower jaw, sending small branches along the canals 
in their roots. 

The Arteria meningea media ascends behind the temporo-maxillary ar- 
ticulation to the foramen spinosum in the spinous process of the sphenoid 
bone, and entering the cranium, divides into an anterior and a posterior 
branch. The anterior branch crosses the great ala of the sphenoid to the 
groove or canal in the anterior inferior angle of the parietal bone, and di- 
vides into branches, which ramify upon the external surface of the dura 
mater, and anastomose with corresponding branches from the opposite 
side. The posterior branch crosses the squamous portion of the temporal 
oone, to the posterior part of the dura mater and cranium. The branches 
of the arteria meningea media are distributed chiefly to the bones of the 
skull; in the middle fossa this artery sends a small branch through the 
hiatus Fallopii to the facial nerve. 

The Meningea parva is a small branch which ascends to the foramen 
ovale, and passes into the skull to be distributed to the Casserian ganglion 
and dura mater. It gives off a twig to the nasal fossae and soft palate. 

The Muscular branches are distributed, as their names imply, to the five 
muscles of the maxillary region ; the temporal branches (temporales pro- 
fun dae) are two in number. 

The Superior dental artery is given off from the internal maxillary, just 
as that vessel is about to make its turn inwards to reach the sphenomax- 
illary fossa. It descends upon the tuberosity of the superior maxillary 
bone, and sends its branches through several small foramina to supply the 
posterior teeth of the upper jaw, and the antrum. The terminal branches 
are continued forwards upon the alveolar process, to be distributed to the 
gums and to the sockets of the teeth. 

The Infra-orbital would appear, from its size, to be the proper con- 
tinuation of the artery. It runs along the infra-orbital canal with the 
superior maxillary nerve, sending branches into the orbit and downwards, 
through canals in the bone, to supply the mucous lining of the antrum 
and the teeth of the upper jaw, and it emerges on the face at the infra- 
orbital foramen. The branch which supplies the incisor teeth is the ante- 
rior dental artery ; on the face the infra-orbital inosculates with the facial 
and transverse facial arteries. 

The Pterygo-palatine is a small branch which passes through the 
pterygo-palatine canal, and supplies the upper part of the pharynx and 
Eustachian tube. 

The Spheno-palatine, or nasal, enters the superior meatus of the nose 
through the spheno-palatine foramen, in company with the nasal branches 
of Meckel's ganglion, and divides into two branches ; one of which is 
distributed in the mucous membrane of the septum, while the other sup- 
plies the mucous membrane of the lateral wall of the nares, together with 
the sphenoid and ethmoid cells. 

The Posterior palatine artery descends along the posterior palatine 
canal, in company with the posterior palatine branches of Meckel's gan- 
glion, to the posterior palatine foramen ; it then curves forward, lying in 
a groove upon the bone, and is distributed to the palate. While in the 
posterior palatine canal it sends a branch backwards, through the small 
posterior palatine foramen, to supply the soft palate, and anteriorly it dis- 



INTERNAL CAROTID ARTERY. 



291 



tributes a branch to the anterior palatine canal, which reaches the nares, 
and inosculates with the branches of the spheno-palatine artery. 

The Vidian branch passes backwards along the pterygoid canal, and is 
distributed to the sheath of the Vidian nerve, and to the Eustachian tube. 



INTERNAL CAROTID ARTERY. 

The internal carotid artery curves slightly outwards from the bifurcation 
of the common carotid, and then ascends nearly perpendicularly through 
the maxillo-pharyngeal space* to the carotid foramen in the petrous bone. 
It next passes inwards, along the carotid canal, forwards by the side of 
the sella turcica, and upwards by the anterior clinoid process, where it 
pierces the dura mater, and divides into three terminal branches. The 
course of this artery is remarkable for the number of angular curves which 
it forms ; one or two of these flexures are sometimes seen in the cervical ( 
portion of the vessel, near the base of the skull ; and by the side of the 
sella turcica it resembles the italic letter s, placed horizontally. 

Relations. — In consideration of its connexions, the artery is divisible 
into a cervical, petrous, cavernous, and cerebral portion. The Cervical, 
portion is in relation posteriorly with the rectus anticus major, sympathetic 
nerve, pharyngeal and laryngeal nerves, which cross behind it, and near 
the carotid foramen with the glossopharyngeal, pneumogastric, and hypo- 
glossal nerves, and partially with the internal jugular vein. Internally it 
is in relation with the side of the pharynx, the tonsil, and the ascending 
pharyngeal artery. Externally with the internal jugular vein, glosso- 
pharyngeal, pneumogastric, and hypo-glossal nerves; and in front with 
the stylo-glossus, and: stylo-pharyngeus muscle, glosso-pharyngeal nerve, 
and parotid gland. 

Plan of the Relations of the Cervical Portion of the Internal Carotid 

Artery. 

In Front. 
Parotid gland, 
Stylo-glossus muscle, 
Stylo-pharyngeus muscle, 
Glosso-pharyngeal nerve. 



Internally. 

Pharynx, 
Tonsil, 

Ascending pharyn- 
geal artery. 



Internal Carotid 
Artery. 



Externally. 

Jugular vein, 
Glosso-pharyngeal, 
Pneumogastric, 
Hypo-glossal nerve. 



Behind. 

Superior cervical ganglion, 
Pneumogastric nerve, 
Glosso-pharyngeal nerve, 
Pharyngeal nerve, 
Superior laryngeal nerve, 
Sympathetic nerve, 
Rectus anticus major. 



The Petrous portion is separated from the bony wall of the carotid 
canal by a lining of dura mater ; it is in relation with the carotid plexus, 
and is covered in by the Casserian ganglion. 

*Far the boundaries of this space see page 188. 



292 OPHTHALMIC ARTERY. 

The Cavernous portion is situated in the inner wall of the cavernous 
sinus, and is in relation by its outer side with the lining membrane of the 
sinus, the sixth nerve, and the ascending branches of the carotid plexus. 
The third, fourth, and ophthalmic nerves are placed in the outer wall of 
the cavernous sinus, and are separated from the artery by the lining mem- 
brane of the sinus. 

The Cerebral portion of the artery is enclosed in a sheath of the arach- 
noid, and is in relation with the optic nerve. At its point of division it is 
situated in the fissure of Sylvius. 

Branches. — The cervical portion of the internal carotid gives off no 
branches : from the other portions are derived the following : — 

Tympanic, 

Anterior meningeal, 

Ophthalmic, 

Anterior cerebral, 

Middle cerebral, 

Posterior communicating, 

Choroidean. 

The Tympanic is a small branch which enters the tympanum through a 
minute foramen in the carotid canal. 

The interior meningeal is distributed to the dura mater and Casserian 
ganglion. 

The Ophthalmic artery arises from the cerebral portion of the internal 
carotid, and enters the orbit through the foramen opticum, immediately to 
the outer side of the optic nerve. It then crosses the optic nerve to the 
inner wall of the orbit, and runs along the lower border of the superior 
oblique muscle, to the inner angle of the eye, where it divides into two 
terminal branches, the frontal and nasal. 

Branches. — The branches of the ophthalmic artery may be arranged into 
two groups : first, those distributed to the orbit and' surrounding parts; 
and, secondly, those which supply the muscles and globe of the eye. 
They are — 

First Group. Second Group. 

Lachrymal, Muscular, 

Supra- orbital, Anterior ciliary, 

Posterior ethmoidal, Ciliary short and long, 

Anterior ethmoidal, Centralis retina). 

Palpebral, 

Frontal, 

Nasal. 

The Lachrymal is the first branch of the ophthalmic artery, and is usu 
ally given off immediately before that artery enters the optic foramen. It 
follows the course of the lachrymal nerve, along the upper border of the 
external rectus muscle, and is distributed to the lachrymal gland. The 
small branches which escape from the gland supply the conjunctiva and 
upper eyelid. The lachrymal artery gives off a malar branch which passes 
through the malar bone into the temporal fossa and inosculates with the 
deep temporal arteries, while some of its branches become subcutaneous 
on the cheek, and anastomose with the transverse facial. 



OPHTHALMIC ARTERY. 293 

The Supra-orbital artery follows the course of the frontal nerve, resting 
on trie levator palpebrae muscle ; it passes through the supra-orbital fora- 
men, and divides into a superficial and deep branch, which are distributed 
to the muscles and integument of the forehead, and to the pericranium. 
At the supra-orbital foramen it sends a branch inwards to the diploe. 

The Ethmoidal arteries, posterior and anterior, pass through the eth- 
moidal foramina, and are distributed to the falx cerebri and to the 
ethmoidal cells and nasal fossae. The latter accompanies the nasal nerve. 

The Palpebral arteries, superior and inferior, are given off* from the 
ophthalmic, near the inner angle of the orbit; they encircle the eyelids, 
forming a superior and an inferior arch near the borders of the lids, between 
the orbicularis palpebrarum and tarsal cartilage. At the outer angle of the 
eyelids the superior palpebral inosculates with the orbitar branch of the 
temporal artery. The inferior palpebral artery sends a branch to the nasal 
duct. 

The Frontal artery, one of the terminal branches of the ophthalmic, 
emerges from the orbit at its inner angle, and ascends along the middle 
of the forehead. It is distributed to the integument, muscles, and peri- 
cranium. 

The Nasal artery, the other terminal branch of the ophthalmic, passes 
out of the orbit above the tendo oculi, and divides into two branches ; one 
of which inosculates with the angular artery, while the other, the dorsalis 
nasi, runs along the ridge of the nose, and is distributed to the integument 
of that organ. The nasal artery sends a small branch to the lachrymal 
sac. 

The Muscular branches, usually two in number, superior and inferior, 
supply the muscles of the orbit ; and upon the anterior aspect of the globe 
of the eye give off the anterior ciliary arteries, which pierce the sclerotic 
near its margin of connection with the cornea, and are distributed to the 
iris. It is the congestion of these vessels that gives rise to the vascular 
zone around the cornea in iritis. 

The Ciliary arteries are divisible into three groups, short, long, and 
anterior. 

The Short ciliary are very numerous ; they pierce the sclerotic around 
the entrance of the optic nerve, and supply the choroid coat and ciliary 
processes. The long ciliary, two in number, pierce the sclerotic on oppo- 
site sides of the globe of the eye, and pass forwards between it and the 
choroid to the iris. They form an arterial circle around the circumference 
of the iris by inosculating with each other, and from this circle branches 
are given off which ramify in the substance of the iris, and form a second 
circle around the pupil. The anterior ciliary are branches of the muscular 
arteries ; they terminate in the great arterial circle of the iris. 

The Centralis retince artery pierces the optic nerve obliquely, and passes 
forwards in the centre of its cylinder to the retina, where it divides into 
branches, which ramify in the inner layer of that membrane. It supplies 
the retina, hyaloid membrane, and zonula ciliaris ; and, by means of a 
branch sent forwards through the centre of the vitreous humour in a tubular 
sheath of the hyaloid membrane, the capsule of the lens. 

The Anterior cerebral artery passes forwards in the great longitudinal 
fissure between the two hemispheres of the brain ; then curves backwards 
along the corpus callosum to its posterior extremity. It gives branches 
25 * 



294 SUBCLAVIAN ARTERY. 

to the olfactory and optic nerves, to the under surface of the anterior lobes, 
the third ventricle, the corpus callosum, and the inner surface of the 
hemispheres. The two anterior cerebral arteries are connected soon after 
their origin by a short anastomosing trunk, the anterior communicating 
artery. 

The Middle cerebral artery, larger than the preceding, passes outwards 
along the fissure of Sylvius, and divides into three principal branches, 
which supply the anterior and middle lobes of the brain, and the island 
of Reil. Near its origin it gives off the numerous small branches which 
enter the substantia perforata, to be distributed to the corpus striatum. 

The Posterior Communicating artery, very variable in size, sometimes 
double, and sometimes altogether absent, passes backwards and inoscu- 
lates with the posterior cerebral, a branch of the basilar artery. Occa- 
sionally it is so large as to take the place of the posterior cerebral 
artery. 

The Choroidean is a small branch which is given off from the internal 
carotid, near the origin of the posterior communicating artery, and passes 
beneath the edge of the middle lobe of the brain to enter the descending 
cornu of the lateral ventricle. It is distributed to the choroid plexus, and 
to the walls of the middle cornu. 



SUBCLAVIAN ARTERY. 

The Subclavian artery, on the right side, arises from the arteria inno- 
minata, opposite the sterno-clavicular articulation, and on the left, from 
the arch of the aorta. The right is consequently shorter than the left, and 
is situated nearer the anterior wall of the chest; it is also somewhat greater 
in diameter, from being a branch of a branch, in place of a division from 
the main trunk. 

The course of the subclavian artery is divisible, for the sake of precision 
and surgical observation, into three portions. The first portion of the 
right and left arteries differs in its course and relations in correspondence 
with the dissimilarity of origin of the respective arteries. The other two 
portions are precisely alike on both sides. 

The first portion, on the right side, ascends obliquely outwards to the 
inner border of the scalenus anticus. On the left side it ascends perpen- 
dicularly to the inner border of that muscle. The second portion curves 
outwards behind the scalenus anticus ; and the third portion passes down- 
wards and outwards beneath the clavicle, to the lower border of the first 
rib, where it becomes the axillary artery. 

Relations. — The first portion, on the right side, is in relation, in front, 
with the internal jugular and subclavian vein at their point of junction, 
and is crossed by the pneumogastric nerve, cardiac nerves, and phrenic 
nerve. Behind and beneath it is invested by the pleura, is crossed by the 
right recurrent laryngeal nerve and vertebral vein, and is in relation with 
the transverse process of the seventh cervical vertebra. The first portion 
on the left side is in relation in front with the pleura, the vena innomi- 
nata, the pneumogastric and phrenic nerves (which lie parallel to it), and 
the left carotid artery. To its inner side is the oesophagus ; to its outer 
Me the pleura ; and behind, the thoracic duct, longus colli, and vertebral 
column. 



SUBCLAVIAN ARTERY — RELATIONS. 



205 



Plan of the Relations of the First Portion of the Right Subclavian Artery 



In Front. 
Internal jugular vein, 
Subclavian vein, 
Pneumogastric nerve, 
Cardiac nerves, 
Phrenic nerve. 



Right Subclavian Artery. 



Behind and Beneath. 

Pleura, 

Recurrent laryngeal nerve, 

Vertebral vein, 

Transverse process of the 7th cervical vertebra. 

Plan of the Relations of the First Portion of the Left Subclavian Artery. 

In Front. 

Pleura, 

Vena innominata, 
Pneumogastric nerve, 
Phrenic nerve, 
Left carotid artery. 



Inner Side. 
(Esophagus. 



Left Subclavian Artery. 



Outer Side 
Pleura 



Behind. 

Thoracic duct, 
Longus colli, 
Vertebral column. 

The Second portion is situated between the two scaleni, and is supported 
by the margin of the first rib. The scalenus anticus separates it from the 
subclavian vein and phrenic nerve. Behind, it is in relation with the 
brachial plexus. 

The Third portion is in relation, in front, with the subclavian vein and 
subclavius muscle ; behind, with the brachial plexus and scalenus posti- 
cus ; below with the first rib ; and above with the supra-scapular artery 
and platysma. 



Plan of the Relations of the Third Portion of the Subclavian Artery, 



In Front. 

Subclavian vein, 
Subclavius. 



Above. 
Supra-scapular artery, 
Platysma myoides. 



Subclavian artery, 
Third portion. 



Below. 
First rib. 



Behind. 

Brachial plexus, 
Scalenus posticus* 



296 



VERTEBRAL AND BASILAR ARTERIES. 



Branches. — The greater part of the branches of the subclavian are given 
off from the artery before it arrives at the margin of the first rib. The 
profunda cervicis and superior intercostal frequently encroach upon the 
second portion, and not unfrequently a branch or branches may be found 
proceeding from the third portion. 

The primary branches are five in number, the first three being ascend- 
ing, and the remaining two descending : they are the — 



Vertebral, 

Thyroid axis, 

Profunda cervicis, 
Superior intercostal, 
Internal mammary. 



' Inferior thyroid, 
Supra-scapular, 
Posterior scapular, 
Superficial cervicis. 



The Vertebral artery is the first and the largest of the branches of 
the subclavian artery ; it ascends through the foramina in the transverse 

processes of all the cervical vertebrse, ex- 
Fig. 148 * cepting the last ; then winds backwards 
around the articulating process of the atlas ; 
and, piercing the dura mater, enters the skull 
through the foramen magnum. The two arte- 
ries unite at the lower border of the pons 
Varolii, to form the basilar artery. In the 
foramina of the transverse processes of the 
vertebrae the artery lies in front of the cer- 
vical nerves. 

Dr. John Davyf has observed that, when 
the vertebral arteries differ in size, the left is 
generally the larger: thus in ninety-eight 
cases he found the left vertebral the larger 
twenty-six times, and the right only eight. 
In the same number of cases he found a 
small band stretching across the cylinder of 
the basilar artery, near the junction of the two vertebral arteries, seventeen 
times, and in a few instances a small communicating trunk between the 
two vertebral arteries previously to their union. I have several times seen 
this communicating branch, and have a preparation now before me in 
which it is exhibited. 

The Basilar artery, so named from its position at the base of the 
brain, runs forwards to the anterior border of the pons Varolii, where it 
divides into four ultimate branches, two to either side. 

Branches. — The branches of the vertebral and basilar arteries are the 
following : — 

* The branches of the right subclavian artery. 1. The arteria innominata. 2. The 
right carotid. 3. The first portion of the subclavian artery. 4. The second portion. 
5. The third portion. 6. The vertebral artery. 7. The inferior thyroid. 8. The thyroid 
axis. 9. The superfieialis cervicis. 10. The profunda cervicis. 11. The posterior 
scapular or transversalis colli. 12. The supra-scapular. 13. The internal mammary 
arteiy. 14. The superior intercostal. 

f Edinburgh Medical and Surgical Journal, 1839. 




BASILAR ARTERY. 297 

C Lateral spinal, 
| Posterior meningeal, 
Vertebral, <{ Anterior spinal, 
Posterior spinal, 
Inferior cerebellar. 

f Transverse, 
i Basilar, < Superior cerebellar, 

[ Posterior cerebral. 

The Lateral spinal branches enter the intervertebral foramina, and are 
distributed to the spinal cord and to its membranes. Where the vertebral 
artery curves around the articular process of the atlas, it gives off several 
muscular branches. 

The Posterior meningeal are one or two small branches which enter the 
cranium through the foramen magnum, to be distributed to the dura mater 
of the cerebellar fossae, and to the falx cerebelli. One branch, described 
by Soemmering, passes into the cranium along the first cervical nerve. 

The Anterior spinal is a small branch which unites with its fellow of the 
opposite side, on the front of the medulla oblongata. The artery formed 
by the union of these two vessels, descends along the anterior aspect of 
the spinal cord, to which it distributes branches. 

The Posterior spinal winds around the medulla oblongata to the poste- 
rior aspect of the cord, and descends on either side, communicating very 
freely with the spinal branches of the intercostal and lumbar arteries. 
Near its commencement it sends a branch upwards to the four ventricle. 

The Inferior cerebellar arteries wind around the upper part of the me- 
dulla oblongata to the under surface of the cerebellum, to which they are 
distributed. They pass between the filaments of origin of the hypo- 
glossal nerve in their course, and anastomose with the superior cerebellar 
arteries. 

The Transverse branches of the basilar artery supply the pons Varolii, 
and adjacent parts of the brain. One of these branches, larger than the 
rest, passes along the crus cerebelli, to be distributed to the anterior bor- 
der of the cerebellum. This may be called the middle cerebellar artery. 

The Superior cerebellar arteries, two of the terminal branches of the 
basilar, wind around the crus cerebri on each side, lying in relation with 
the fourth nerve, and are distributed to the upper surface of the cerebellum, 
inosculating with the inferior cerebellar. This artery gives off a small 
branch, which accompanies the seventh pair of nerves into the meatus 
auditorius internus. 

The Posterior cerebral arteries, the other two terminal branches of the 
basilar, wind around the crus cerebri at each side, and are distributed to 
the posterior lobes of the cerebrum. They are separated from the supe- 
rior cerebellar arteries, near their origin, by the third pair of nerves, and are 
in close relation with the fourth pair, in their course around the crura 
cerebri. Anteriorly, near their origin, they give off a tuft of small vessels, 
which enter the locus perforatus, and they receive the posterior communi- 
cating arteries from the internal carotid. They also send a branch to the 
velum interpositum and plexus choroides. 

The communications established between the anterior cerebral arteries 
in front, and the internal carotids and posterior cerebral arteries behind, 
by the communicating arteries, constitute the circle of Willis. This 



29S 



SUPRA-SCAPULAR ARTERY. 



remarkable communication at the base of the brain is formed by the ante- 
rior communicating branch, anterior cerebrals, and internal carotid arteries, 



Fig. 149* 




in front, and by the posterior communicating, posterior cerebrals, and 
basilar artery, behind. 

The Thyroid axis is a short trunk, which divides almost immediately 
after its origin into four branches, some of which are occasionally branches 
of the subclavian artery itself. 

The Inferior thyroid artery ascends obliquely in a serpentine course 
behind the sheath of the carotid vessels, to the inferior part of the thyroid 
gland, to which it is distributed ; it sends branches also to the trachea, 
lower part of the larynx, and oesophagus. It is in relation with the middle 
cervical ganglion of the sympathetic, which lies in front of it. 

The Supra-scapular artery (transversalis humeri) passes obliquely 
outwards behind the clavicle, and over the ligament of the supra-scapular 
notch, to the supra-spinatus fossa. It crosses in its course the scalenus 
anticus muscle, phrenic nerve, and subclavian artery, is distributed to the 

* The circle of Willis. The arteries have references only on one side, on account of 
their symmetrical distribution. 1. The vertebral arteries. 2. The two anterior spinal 
branches uniting to form a single vessel. 3. One of the posterior spinal arteries. 4. The 
posterior meningeal. 5. The inferior cerebellar. 6. The basilar artery giving off its 
transverse branches to either side. 7. The superior cerebellar artery. 8. The posterior 
cerebral. 9. The posterior communicating branch of the internal carotid. 10. The in- 
ternal carotid artery, showing the curvatures it makes within the skull. 11. The oph- 
thalmic artery divided across. 12. The middle cerebral artery. 13. The anterior cere- 
bral arteries connected by, 14. The anterior communicating artery. 



INTERNAL MAMMARY ARTERY. 299 

muscles on the dorsum of the scapula, and inosculates with the posterior 
scapular, and beneath the acromion process with the dorsal branch of the 
subscapular artery. At the supra-scapular notch it sends a large branch to 
the trapezius muscle. The supra-scapular artery is not unfrequently a 
branch of the subclavian. 

The Posterior scapular artery (transversalis colli) passes trans- 
versely across the subclavian triangle at the root of the neck, to the supe- 
rior angle of the scapula. It then descends along the posterior border of 
that bone to its inferior angle, where it inosculates with the subscapular 
artery, a branch of the axillary. In its course across the neck it passes in 
front of the scalenus anticus, and across the brachial plexus ; in the rest 
of its course it is covered in by the trapezius, levator anguli scapulas, 
rhomboideus minor, and rhomboideus major muscles. Sometimes it passes 
behind the scalenus anticus, and between the nerves, which constitute the 
brachial plexus. This artery, which is very irregular in its origin, pro- 
ceeds more frequently from the third portion of the subclavian artery than 
from the first. 

The posterior scapular gives branches to the neck, and opposite the 
angle of the scapula inosculates with the profunda cervicis. It supplies 
the muscles along the posterior border of the scapula, and establishes an 
important anastomotic communication between the branches of the exter- 
nal carotid, subclavian, and axillary arteries. 

The Superficialis cervicis artery (cervicalis anterior) is a small 
vessel, which ascends upon the anterior tubercles of the transverse pro- 
cesses of the cervical vertebrae, lying in the groove between the scalenus 
anticus and rectus anticus major. It is distributed to the deep muscles 
and glands of the neck, and sends branches through the intervertebral 
foramina to supply the spinal cord and its membranes. 

The Profunda cervicis (cervicalis posterior) passes backwards between 
the transverse processes of the seventh cervical and first dorsal vertebras, 
and then ascends the back part of the neck, between the complexus and 
semi-spinalis colli muscles. It inosculates above with the princeps cervicis 
of the occipital artery, and below, by a descending branch, with the pos- 
terior scapular. 

The Superior intercostal artery descends behind the pleura upon 
the necks of the first two ribs, and inosculates with the first aortic inter- 
costal. It gives off two branches which supply the first two intercostal 
spaces. 

The Internal mammary artery descends by the side of the sternum, 
resting against the costal cartilages, to the diaphragm ; it then pierces the 
anterior fibres of the diaphragm, and enters the sheath of the rectus, where 
it inosculates with the epigastric artery, a branch of the external iliac. In 
the upper part of its course it is crossed by the phrenic nerve, and lower 
down lies between the triangularis sterni and the internal intercostal 
muscles. 

The Branches of the internal mammary are, — 

Anterior intercostal, Mediastinal, 

Mammary, Pericardiac, 

Comes neivi phrenici, Musculo-phrenic. 



300 AXILLARY ARTERY. 

The interior intercostals supply the intercostal muscles of the front of 
the chest, and inosculate with the aortic intercostal arteries. Each of the 
first three anterior intercostals gives off a large branch to the mammary 
gland, which anastomoses freely with the thoracic branches of the axillary 
artery ; the corresponding branches from the remaining intercostals supply 
the integument and pectoralis major muscle. There are usually two an- 
terior intercostal arteries in each space. 

The Comes nervi phrenici is a long and slender branch which accom- 
panies the phrenic nerve. 

The mediastinal and pericardiac branches are small vessels distributed 
to the anterior mediastinum, the thymus gland, and pericardium. 

The Musculo-phrenic artery winds along the attachment of the diaphragm 
to the ribs, supplying that muscle, and sending branches to the inferior 
intercostal spaces. " The mammary arteries," says Dr. Harrison, " are 
remarkable for the number of their inosculations, and for the distant parts 
of the arterial system which they serve to connect. They anastomose with 
each other, and their inosculations, with the thoracic aorta, encircle the 
thorax. On the parietes of this cavity their branches connect the axillary 
and subclavian arteries; on the diaphragm they form a link in the chain 
of inosculations between the subclavian artery and abdominal aorta, and 
in the parietes of the abdomen they form an anastomosis most remarkable 
for the distance between those vessels which it serves to connect ; namely, 
the arteries of the superior and inferior extremities." 

Varieties of the subclavian Arteries. — Varieties in these arteries are. rare; 
that which most frequently occurs is the origin of the right subclavian, 
from the left extremity of the arch of the aorta, below the left subclavian 
artery. The vessel, in this case, curves behind the oesophagus and right 
carotid artery, and sometimes between the oesophagus and trachea, to the 
upper border of the first rib on the right side of the chest, where it assumes 
its ordinary course. In a case* of subclavian aneurism on the right side, 
above the clavicle, which happened during the summer of 1839, Mr. Lis- 
ton proceeded to perform the operation of tying the carotid and subclavian 
arteries at their point of division from the innominata. Upon reaching 
the spot where the bifurcation should have existed, he found that there 
was no subclavian artery. With the admirable self-possession which dis- 
tinguishes this eminent surgeon in all cases of emergency, he continued 
his dissection more deeply, towards the vertebral column, and succeeded 
in securing the artery. It was ascertained after death, that the arteria 
innominata was extremely short, and that the subclavian was given off 
within the chest from the posterior aspect of its trunk, and pursued a deep 
course to the upper margin of the first rib. In a preparation which was 
shown to me in Heidelberg some years since by Professor Tiedemann, 
the right subclavian artery arose from the thoracic aorta, as low down as 
the fourth dorsal vertebra, and ascended from that point to the border of 
the first rib. Varieties in the branches of the subclavian are not unfre- 
quent ; the most interesting is the origin of the left vertebral from the arch 
of the aorta, of which I possess several preparations. 

AXILLARY ARTERY. 

The axillary artery forms a gentle curve through the middle of the 

* This case is recorded in the Lancet, vol. i. 1839-40, pp. 37 and 419. 



AXILLARY ARTERY — BRANCHES. 



301 



axillary space from the lower border of the first rib to the lower border of 
the latissimus dorsi, where it becomes the brachial. 

Relations. — After emerging from beneath the margin of the costo-cora- 
coid membrane, it is in relation with the axillary vein, which lies at first 
to the inner side, and then in front of the artery. Near the middle of the 
axilla it is embraced by the two heads of the median nerve, and is covered 
in by the pectoral muscles. Upon the inner or thoracic side it is in rela- 
tion, first, with the first intercostal muscle ; it next rests upon the first 
serration of the serratus magnus ; and is then separated from the chest by 
the brachial plexus of nerves. By its outer or humeral side it is at first 
separated from the brachial plexus by a triangular interval of areolar tis- 
sue ; it next rests against the tendon of the subscapularis muscle ; and 
thirdly, upon the coraco-brachialis muscle. 

The relations of the axillary artery may be thus arranged : — 



In Front. 
Pectoralis major, 
Pectoralis minor, 
Pectoralis major. 



Inner or Thoracic Side. 
First intercostal muscle, 
First serration of serra- 
tus magnus, 
Plexus of nerves. 



Outer or Humeral Side. 
Plexus of nerves, 
Tendon of sub- 
scapularis, 
Coraco-brachialis. 



Branches. — The branches of the Axillary artery are seven in number : — 

Thoracica acromialis, Fig. 150.* 

Superior thoracic, 

Inferior thoracic, ^^ 

Thoracica axillaris, ^ 

Subscapular, 

Circumflex anterior, 

Circumflex posterior. 

The thoracica acromialis and superior 
thoracic are found in the triangular space 
above the pectoralis minor. The inferior 
thoracic and thoracica axillaris, below the 
pectoralis minor. And the three remaining 
branches below the lower border of the sub- 
scapularis. 

The Thoracica acromialis is a short trunk 
which ascends to the space above the pec- 
toralis minor muscle, and divides into three 
branches, thoracic, which is distributed to 
the pectoral muscles and mammary gland ; 
acromial, which passes outwards to the 
acromion, and inosculates with branches of 
the supra-scapular artery ; and descending, 
which follows the interspace between the 
deltoid and pectoralis major muscles, and 
is in relation with the cephalic vein. 

* The axillary and brachial artery, with their branches. 1. The deltoid muscle. 2. 
The biceps. 3. The tendinous process given off from the tendon of the biceps, to the 
deep fascia of the fore-arm. It is this process which separates the median basilic vein 
from the brachial artery. 4. The outer border of the brachialis amicus muscle. 5 The 
supinator longus. 0. The coraco-brachialis. 7. The middle portion of the triceps 

i 




302 VARIETIES OF THE AXILLARY ARTERY. 

The Superior thoracic (short) frequently arises by a common trunk with 
the preceding ; it runs along the upper border of the pectoralis minor, 
and is distributed to the pectoral muscles and mammary gland, inosculat- 
ing with the intercostal and mammary arteries. 

The Inferior thoracic (long external mammary) descends along the 
lower border of the pectoralis minor to the side of the chest. It is distri- 
buted to the pectoralis major and minor, serratus magnus, and subscapu- 
laris muscle, to the axillary glands and mammary gland; inosculating 
with the superior thoracic, intercostal, and mammary arteries. 

The Thoracica axillaris is a small branch distributed to the plexus of 
nerves and glands in the axilla. It is frequently derived from one of the 
other thoracic branches. 

The Subscapular artery, the largest of the branches of the axillary, runs 
along the lower border of the subscapularis muscle, to the inferior angle 
of the scapula, where it inosculates with the posterior scapular, a branch 
of the subclavian. It supplies, in its course, the muscles on the under 
surface and inferior border of the scapula, and the side of the chest. At 
about an inch and a half from the axillary, it gives off a large branch, the 
dorsalis scapulce, which passes backwards through the triangular space 
bounded by the teres minor, teres major, and scapular head of the triceps, 
and beneath the infra -spinatus to the dorsum of the scapula, where it is 
distributed, inosculating with the supra-scapular and posterior scapular 
arteries. 

The Circumflex arteries wind around the neck of the humerus. The 
anterior ,ver y small, passes beneath the coraco-brachialis and short head 
of the biceps, and sends a branch upwards along the bicipital groove to 
supply the shoulder joint. 

The Posterior circumflex, of larger size, passes backwards through the 
quadrangular space bounded by the teres minor and major, the scapular 
head of the triceps and the humerus, and is distributed to the deltoid 
muscle and joint. Sometimes this artery is a branch of the superior pro- 
funda of the brachial. It then ascends behind the tendon of the teres 
major, and is distributed to the deltoid without passing through the quad- 
rangular space. The posterior circumflex artery sends branches to the 
shoulder joint. 

Varieties of the Axillary artery. — The most frequent peculiarity of this 
kind is the division of the vessel into two trunks of equal size : a muscular 
trunk, which gives off some of the ordinary axillary branches and supplies 
the upper arm, and a continued trunk, which represents the brachial ar- 
tery. The next most frequent variety is the high division of the ulnai 
which passes down the arm by the side of the brachial artery, and superfi- 
cially to the muscles proceeding from the inner condyle, to its ordinary 
distribution in the hand. In this course it lies immediately beneath the 

muscle. 8. Its inner head. 9. The axillary artery. 10. The brachial artery; — a dark 
line marks the limit between these two vessels. 11. The thoracica acromialis artery 
dividing into its three branches; the number rests upon the coracoid process. 12. The 
superior and inferior thoracic arteries. 13. The serratus magnus muscle. 14. The 
subscapular artery. The posterior circumflex and thoracica axillaris branches are seen 
in the figure between the inferior thoracic and subscapular. The anterior circumflex 
is observed, between the two heads of the biceps, crossing the neck of the humerus. 
15. The superior profunda artery. 16. The inferior profunda. 17. The anaetomotica 
magna inosculating inferiorly with the anterior ulnar recurrent. 18. The termination 
of the superior profunda, inosculating with the radial recurrent in the interspace be- 
tween the brachials amicus and supinator longus. 



BRACHIAL ARTERY. 



303 



deep fascia of the fore-arm, and may be seen and felt pulsating beneath 
the integument. The high division of the radial from the axillary is rare. 
In one instance, I saw the axillary artery divide into three branches of 
nearly equal size which passed together down the arm, and* at the bend 
of the elbow resolved themselves into radial, ulnar, and interosseous. But 
the most interesting variety, both in a physiological and surgical sense, is 
tiiat described by Dr. Jones Quain, in his " Elements of Anatomy." " I 
found in the dissecting-room, a few years ago, a variety not hitherto no- 
ticed ; it was at first taken for the ordinary high division of the ulnar 
artery. The two vessels descended from the point of division at the bor- 
der of the axilla, and lay parallel with one another in their course through 
the arm ; but instead of diverging, as is usual, at the bend of the elbow, 
they converged, and united so as to form a short trunk which soon divided 
again into the radial and ulnar arteries in the regular way." In a subject, 
dissected by myself, this variety existed in both arms ; and I have seen 
several instances of a similar kind. 



BRACHIAL ARTERY. 

The Brachial artery passes down the inner side of the arm, from the 
lower border of the latissimus dorsi to the bend of the elbow, where it di- 
vides into the radial and ulnar arteries. 

Relations. — In its course downwards, it rests upon the coraco-brachialis 
muscle, internal head of the triceps, brachialis anticus, and the tendon of 
the biceps. To its inner side is the ulnar nerve ; to the outer side, the 
coraco-brachialis and biceps muscles ; in front it has the basilic vein, and 
is crossed by the median nerve. Its relations, within its sheath, are the 
venae comites. 

Plan of the Illations of the Brachial Mery. 

In Front. 

Basilic vein, 
Deep fascia, 
Median nerve. 



Inner Side. 
Ulnar nerve. 



Brachial artery. 



Outer Side. 

Coracobrachial is, 
Biceps. 



Behind. 

Short head of triceps, 
Coraco-brachial is, 
Brachialis anticus, 
Tendon of biceps. 

The branches of the brachial artery are, the — 

Superior profunda, 
Inferior profunda, 
Anastomotica magna, 
Muscular. 

The Superior profunda arises opposite the lower border of the latissimus 
dorsi, and winds around the humerus, between the triceps and the bone, 
to the space between the brachialis anticus and supinator longus, where it 



304 



RADIAL ARTERY. 



Fig. 151* 



inosculates with the radial recurrent branch. It 
accompanies the musculo-spiral nerve. In its 
course it gives off the posterior articular artery, 
which descends to the elbow joint, and a more 
superficial branch which inosculates with the in- 
terosseous articular artery. 

The Inferior profunda arises from about the 
middle of the brachial artery, and descends to 
the space between the inner condyle and olecra- 
non in company with the ulnar nerve, where it 
inosculates with the posterior ulnar recurrent. 

The Anastomotica magna is given off nearly 
at right angles from the brachial, at about two 
inches above the joint. It passes directly inwards, 
and divides into two branches which inosculate 
with the anterior and posterior ulnar recurrent 
arteries and with the inferior profunda. 

The Muscular branches are distributed to the 
muscles in the course of the artery, viz. to the 
coraco-brachialis, biceps, deltoid, brachialis an- 
ticus and triceps. 

Varieties of the Brachial Artery. — The most 
frequent peculiarity in the distribution of branches 
from this artery is the high division of the radial, 
which arises generally from about the upper third 
of the brachial artery, and descends to its normal 
position at the bend of the elbow. The ulnar 
artery sometimes arises from the brachial at 
about two inches above the elbow, and pursues 
either a superficial or deep course to the wrist ; 
and, in more than one instance, I have seen the interosseous artery arise 
from the brachial a little above the bend of the elbow. The two profunda 
arteries occasionally arise by a common trunk, or there may be two superior 
profunda?. 

RADIAL ARTERY. 

The Radial artery, one of the divisions of the brachial, appears, from 
its direction, to be the continuation of that trunk. It runs along the radial 
side of the fore-arm, from the bend of the elbow to the wrist ; it there 
turns around the base of the thumb, beneath its extensor tendons, and 

* The arteries of the fore-arm. 1. The lower part of the biceps muscle. 2. The inner 
condyle of the humerus with the humeral origin of the pronator radii teres and flexor 
carpi radialis divided across. 3. The deep portion of the pronator radii teres. 4. The 
supinator longus muscle. 5. The flexor longus pollicis. 6. The pronator quadratus. 7. 
The flexor profundus digitorum. 8. The flexor carpi ulnaris. 9. The annular ligament 
with the tendons passing beneath it into the palm of the hand ; the figure is placed on 
the tendon of the palmaris longus muscle, divided close to its insertion. 10. The brachial 
artery. 11. The anastomotica magna inosculating superiorly with the inferior profunda, 
and inferiorly with the anterior ulna recurrent. 12. The radial artery. 13. The radial 
recurrent artery inosculating with the termination of the superior profunda. 14. The 
superficial voIec. 15. The ulnar artery. 16. Its superficial palmar arch giving off di- 
gital branches to three fingers and a half. 17. The magna pollicis and radialis arteries. 
18. The posterior ulnar recurrent. 19. The anterior interosseous artery. 20. The poste- 
rior interosseous, as it is passing through the interosseous membrane. 




RADIAL ARTERY. 



305 



passes between the two heads of the first dorsal interosseous muscle, into 
the palm of the hand. It then crosses the metacarpal bones to the ulnar 
side of the hand, forming the deep palmar arch, and terminates by inoscu- 
lating with the superficial palmar arch. 

In the upper half of its course, the radial artery is situated between the 
supinator longus muscle, by which it is overlapped superiorly, and the 
pronator radii teres ; in the lower half, between the tendons of the supina- 
tor longus and flexor carpi radialis. It rests in its course downwards, 
upon the supinator brevis, pronator radii teres, radial origin of the flexor 
sublimis, flexor longus pollicis, and pronator quadratus ; and is covered 
in by the integument and fasciae. At the wrist it is situated in contact 
with the dorsal carpal ligaments and beneath the extensor tendons of the 
thumb ; and, in the palm of the hand, beneath the flexor tendons. It is 
accompanied by venae comites throughout its course, and by its middle 
third is in close relation with the radial nerve. 

Plan of the Relations of the Radial Artery in the Fore-arm. 

In Front. 
Deep fascia, 
Supinator longus. 



Inner Side. 

Pronator radii teres, 
Flexor carpi radialis. 



Radial artery. 



Outer side. 

Supinator longus, 
Radial nerve (middle 
third of its course). 



Wrist, 



Hand, 



Behind. 

Supinator brevis, 
Pronator radii teres, 
Flexor sublimis digitorum, 
Flexor longus pollicis. 
Pronator quadratus, 
Wrist joint. 

The Branches of the radial artery may be arranged into three groups, 
corresponding with the three • regions, the fore-arm, the wrist, and the 
hand ; they are — 

*-* . IS 1 *' 

' Superficialis volee, 

Carpalis anterior, 

Carpalis posterior, 

Metacarpalis, 

Dorsales pollicis. 
' Princeps pollicis, 

Radialis indicis, 

Interosseae, 

Perforantes. 

v. 

The Recurrent branch is given off immediately below the elbow ; it as- 
cends in the space between the supinator longus and brachialis anticus to 
supply the joint, and inosculates with the terminal branches of the superior 
profunda. This vessel gives off numerous muscular branches. 

The Muscular branches are distributed to the muscles on the radial side 
of the fore-arm. 

26* tt 



306 ULNAR ARTERY. 

The Superjicialis voice is given off from the radial artery while at the 
wrist. It passes between the fibres of the abductor pollicis muscle, and 
inosculates with the termination of the ulnar artery, completing the super- 
ficial palmar arch. This artery is very variable in size, being sometimes 
as large as the continuation of the radial, and at other times a mere mus- 
cular ramusculus, or entirely wanting ; when of large size it supplies the 
palmar side of the thumb and the radial side of the index finger. 

The Carpal branches are intended for the supply of the wrist, the ante- 
rior carpal in front, and the posterior, the larger of the two, behind. The 
carpalis posterior crosses the carpus transversely to the ulnar border of the 
hand, where it inosculates with the posterior carpal branch of the ulnar 
artery. Superiorly it sends branches which inosculate with the termination 
of the anterior interosseous artery ; inferiorly it gives off posterior interos- 
seous branches, which anastomose with the perforating branches of the 
deep palmar arch, and then run forward upon the dorsal interossei mus- 
cles. 

The Metacarpal branch runs forward on the second dorsal interosseous 
muscle, and inosculates with the digital branch of the superficial palmar 
arch, which supplies the adjoining sides of the index and middle fingers. 
Sometimes it is of large size, and the true continuation of the radial ar- 
tery. 

The Dorsales pollicis are two small branches which run along the sides 
of the dorsal aspect of the thumb. 

The Princeps pollicis descends along the border of the metacarpal bone, 
between the abductor indicis and adductor pollicis to the base of the first 
phalanx, where it divides into two branches, which are distributed to the 
two sides of the palmar aspect of the thumb. 

The Radialis indicis is also situated between the abductor indicis and 
the adductor pollicis, and runs along the radial side of the index finger, 
forming its collateral artery. This vessel is frequently a branch of the 
princeps pollicis. 

The Interossece, three or four in number, are branches of the deep pal- 
mar arch ; they pass forward upon the interossei muscles, and inosculate 
with the digital branches of the superficial arch, opposite the heads of the 
metacarpal bones. 

The P erf or antes, three in number, pass directly backwards, between the 
heads of the dorsal interossei muscles, and inosculate with the posterior 
interosseous arteries. 

ULNAR ARTERY. 

The Ulnar artery, the other division of the brachial artery, crosses the 
arm obliquely to the commencement of its middle third ; it then runs down 
the ulnar side of the fore-arm to the wrist, crosses the annular ligament, 
and forms the superficial palmar arch, which terminates by inosculating 
with the superficialis volae. 

Relations. — In the upper or oblique portion of its course, it lies upon 
the brachialis anticus and flexor profundus digitorum ; and is covered in 
by the superficial layer of muscles of the fore-arm and by the median nerve. 
In the second part of its course, it is placed upon the flexor profundus and 
pronator quadratus, lying between the flexor carpi ulnaris and flexor sub- 
hmis digitorum. While crossing the annular ligament it is protected from 
injury by a strong tendinous arch, thrown over it from the pisiform bone : 



ULNAR ARTERY — BRANCHES. 



307 



and in the palm it rests upon the tendons of the flexor sublimis, being 
covered in by the palmaris brevis muscle and palmar fascia. It is accom- 
panied in its course by the venae comites, and is in relation with the ulnar 
nerve for the lower two-thirds of its extent. 

Plan of the Relations of the Ulnar Artery. 

In Front. 

Deep fascia, 

Superficial layer of muscles, 

Median nerve. 

In the Hand. 

Tendinous arch from the pisiform bone, 

Palmaris brevis muscle, 

Palmar fascia. 



Inner Side. 
Flexor carpi ulnaris, 
Ulnar nerve (lower 
two-thirds). 



Ulnar artery. 



Outer Side. 
Flexor sublimis digi- 
torum. 



Behind. 

Brachialis amicus, 

Flexor profundus digitorum, 

Pronator quadratus. 

In the Hand. 

Annular ligament, 
Tendons of the flexor sublimis digitorum. 



The Branches of the ulnar artery may be arranged, like those of the 
Tadial, into three groups : — 



^^-^'i Interosseous, 



Wrist, 
Hand, 



Anterior ulnar recurrent, 
Posterior ulnar recurrent, 

Anterior interosseous, 
Posterior interosseous. 
Muscular. 
{ Carpalis anterior, 
( Carpalis posterior. 
Digitales. 



The Anterior ulnar recurrent arises immediately below the elbow, and 
ascends in front of the joint between the pronator radii teres and brachialis 
anticus, where it inosculates with the anastomotica magna and inferior 
profunda. The two recurrent arteries frequently arise by a common 
trunk. 

The Posterior ulnar recurrent, larger than the preceding, arises imme- 
diately below the elbow joint, and passes backwards beneath the origins 
of the superficial layer of muscles ; it then ascends between the two heads 
of the flexor carpi ulnaris, and beneath the ulnar nerve, and inosculates 
with the inferior profunda and anastomotica magna. 

The Common interosseous artery is a short trunk which arises from the 
ulnar, opposite the bicipital tuberosity of the radius. It divides into two 
branches, the anterior and posterior interosseous arteries. 



308 BRANCHES OF THE THORACIC AORTA. 

The Anterior interosseous passes down the fore-arm upon the interosse- 
ous membrane, between the flexor profundus digitorum and flexor longus 
pollicis, and behind the pronator quadratus. In the latter position it 
pierces the interosseous membrane, and descends to the back of the wrist, 
where it inosculates with the posterior carpal branches of the radial and 
ulnar. It is retained in connexion with the interosseous membrane by 
means of a thin aponeurotic arch. 

The anterior interosseous artery sends a branch to the median nerve, 
which it accompanies into the hand. The median artery is sometimes of 
large size, and occasionally takes the place of the superficial palmar arch. 

The Posterior interosseous artery passes backwards through an opening 
between the upper part of the interosseous membrane and the oblique 
ligament, and is distributed to the muscles on the posterior aspect of the 
fore- arm. It gives off a recurrent branch, which returns upon the elbow 
between the anconeus, extensor carpi ulnaris and supinator brevis muscles, 
and anastomoses with the posterior terminal branches of the superior pro- 
funda. 

The Muscular branches supply the muscles situated along the ulnar 
border of the fore-arm. 

The Carpal branches, anterior and posterior, are distributed to the an- 
terior and posterior aspects of the wrist joint, where they inosculate with 
corresponding branches of the radial artery. 

The Digital branches are given off from the superficial palmar arch, and 
are four in number. The first and smallest is distributed to the ulnar side 
of the little finger. The other three are short trunks, which divide be- -^^ 
tween the heads of the metacarpal bones, and form the collateral branch""""'" 4 *' 
of the radial side of the little finger, the collateral branches of the ring and 
middle fingers, and the collateral branch of the ulnar side of the index 
finger. 

The Superficial palmar arch receives the termination of the deep palmar 
arch from between the abductor minimi digiti and flexor brevis minimi 
digiti near their origins, and terminates by inosculating with the superfi- 
cialis volae upon the ball of the thumb. The communication between the 
superficial and deep arch is generally described as the communicating 
branch of the ulnar artery. 

The mode of distribution of the arteries to the hand is subject to fre- 
quent variety. 

BRANCHES OF THE THORACIC AORTA. 

Bronchial, 

Oesophageal, 

Intercostal. 

The Bronchial arteries are four in number, and vary both in size 
and origin. They are distributed to the bronchial glands and tubes, and 
send branches to the oesophagus, pericardium, and left auricle of the heart. 
These are the nutritious vessels of the lungs. 

The CEsophageal arteries are numerous small branches ; they arise 
from the anterior part of the aorta, are distributed to the oesophagus, and 
establish a chain of anastomoses along that tube : the superior inosculate 
with the bronchial arteries, and with cesophageal branches of the inferior 



BRANCHES OF THE ABDOMINAL AORTA. 309 

thyroid arteries ; and the inferior with similar branches of the phrenic and 
gastric arteries. 

The Intercostal, or posterior intercostal arteries, arise from the poste- 
rior part of the aorta ; they are nine in number on each side, the two su- 
perior spaces being supplied by the superior intercostal artery, a branch 
of the subclavian. The right intercostals are longer than the left, on ac- 
count of the position of the aorta. They ascend somewhat obliquely from 
their origin, and cross the vertebral column behind the thoracic duct, vena 
azygos major, and sympathetic nerve, to the intercostal spaces, the left 
passing beneath the superior intercostal vein, the vena azygos minor and 
sympathetic. In the intercostal spaces, or rather, upon the external inter- 
costal muscles, each artery gives off a dorsal branch, which passes back 
between the transverse processes of the vertebrae, lying internally to the 
middle costo-transverse ligament, and divides into a spinal branch, which 
supplies the spinal cord and vertebra?, and a muscular branch which is 
distributed to the muscles and integument of the back. The artery then 
comes into relation with its vein and nerve, the former being above and 
the latter below, and divides into two branches which run along the bor- 
ders of contiguous ribs between the two planes of intercostal muscles, and 
anastomose with the anterior intercostal arteries, branches of the internal 
mammary. The branch corresponding with the lower border of each rib 
is the larger of the two. They are protected from pressure during the 
action of the intercostal muscles, by little tendinous arches thrown across 
the^and attached by each extremity to the bone. 

BRANCHES OF THE ABDOMINAL AORTA. 

Phrenic, 

C Gastric, 
Coeliac axis < Hepatic, 

( Splenic. 
Superior mesenteric, 
Spermatic, 
Inferior mesenteric, 
Supra-renal, 
Renal, 
Lumbar, 
Sacra media. 

The Phrenic arteries are given off from the anterior part of the aorta 
as soon as' that trunk has passed through the aortic opening. Passing 
obliquely outwards upon the under surface of the diaphragm, each artery 
divides into two branches, an internal branch, which runs forwards, and 
inosculates with its fellow of the opposite side in front of the oesophageal 
opening ; and an external branch, which proceeds outwards towards the 
great circumference of the muscle, and sends branches to the supra-renal 
capsules. The phrenic arteries inosculate with branches of the internal 
mammary inferior intercostal, epigastric, oesophageal, gastric, hepatic, and 
supra-renal arteries. They are not unfrequently derived from the cceliac 
axis, or from one of its divisions, and sometimes they give off the supra- 
renal arteries. r 



310 



GASTRIC AND HEPATIC ARTERIES. 



The Cceliac axis (xoiXia, ventriculus) is the first single trunk given off 
from the abdominal aorta. It arises opposite the upper border of the first 

lumbar vertebra, is about half an 
Fi s- l52 -* inch in length, and divides into 

three large branches, gastric, he- 
patic, and splenic. 

Relations. — The trunk of the 
coeliac axis has in relation with it, 
in front, the lesser omentum ; on 
the right side the right semilunar 
ganglion and lobus Spigelii of the 
liver ; on the left side the left 
semilunar ganglion and cardiac 
portion of the stomach ; and below, 
the upper border of the pancreas 
and lesser curve of the stomach. 
It is completely surrounded by the 
solar plexus. 

The Gastric artery (coronaria 
ventriculi), the smallest of the three 
branches of the cceliac axis, ascends 
between the two layers of the lesser 
omentum to the cardiac orifice of 
the stomach, then runs along* the 
lesser curvature to the pylorus, 
and inosculates with the pyloric 
branch of the hepatic. It is dis- 
tributed to the lower extremity of 
the oesophagus and lesser curve of 
the stomach, and anastomoses with 
the oesophageal arteries and vasa brevia of the splenic artery. 

The Hepatic artery curves forwards, and ascends along the right 
border of the lesser omentum to the liver, where it divides into two 
branches (right and left), which enter the transverse fissure, and are dis 
tributed along the portal canals to the right and left lobes, f It is in rela- 
tion, in the right border of the lesser omentum, with the ductus communis 
choledochus and portal vein, and is surrounded by the hepatic plexus of 
nerves and numerous lymphatics. There are sometimes two hepatic 
arteries, in which case one is derived from the superior mesenteric 
artery. 

* The abdominal aorta with its branches. 1. The phrenic arteries. 2. The coeliac 
axis. 3. The gastric artery. 4. The hepatic artery, dividing into the right and left 
hepatic branches. 5. The splenic artery, passing outwards to the spleen. 6. The 
supra-renal artery of the right side. 7. The right renal artery, which is longer than the 
left, passing outwards to the right kidney. 8. The lumbar arteries. 9. The superior 
mesenteric artery. 10. The two spermatic arteries. 11. The inferior mesenteric artery. 
12. The sacra media. 13. The common iliacs. 14. The internal iliac of the right side. 
15. The external iliac artery. 16. The epigastric artery. 17. The circumflexa ilii 
artery. 18. The femoral artery. 

f For the mode of distribution of the hepatic artery within the liver, see the " Minute 
Anatomy" of that organ in the Chapter on the Viscera. 




SPLENIC ARTERY. 311 

The Branches of the hepatic artery are, the 

Pyloric, 

^ aay \ Gastro-epiploica dextra, 

Gastro-duodenaJis, < „ *• 1 j r 

( Pancreatico-duodenalis. 

Cystic. 

The Pyloric branch, given off from the hepatic near the pylorus, is dis- 
tributed to the commencement of the duodenum and to the lesser curve 
of the stomach, where it inosculates with the gastric artery. 

The Gastro-duodenalis artery is a short but large trunk, which descends 
behind the pylorus, and divides into two branches, the gastro-epiploica 
dextra, and pancreatico-duodenalis. Previously to its division, it gives 
off some inferior pyloric branches to the small end of the stomach. 

The Gastro-epiploica dextra runs along the great curve of the stomach 
lying between the two layers of the great omentum, and inosculates at 
about its middle with the gastro-epiploica sinistra, a branch of the splenic 
artery. It supplies the great curve of the stomach and the great omentum ; 
hence the derivation of its name. 

The Pancreatico-duodenalis curves along the fixed border of the duo- 
denum, partly concealed by the attachment of the pancreas, and is distri- 
buted to the pancreas and duodenum. It inosculates inferiorly with the 
first jejunal, and with the pancreatic branches of the superior mesenteric 
artery. 

The Cystic artery, generally a branch of the right hepatic, is of small 
size, and ramifies between the coats of the gall-bladder, previously to its 
distribution to the mucous membrane. 

The Splenic artery, the largest of the three branches of the cceliac 
axis, passes horizontally to the left along the upper border of the pancreas, 
and divides into five or six large branches, which enter the hilus of the 
spleen, and are distributed to its structure. In its course it is tortuous 
and serpentine, and frequently makes a complete turn upon itself. It lies 
in a narrow groove in the upper border of the pancreas, and is accom- 
panied by the splenic vein, and by the splenic plexus of nerves. 

The Branches of the splenic artery are the — 

Pancreaticae parvse, 
Pancreatica magna, 

O 7 

. Vasa brevia, 
Gastro-epiploica sinistra. 

The Pancreatica parva are numerous small branches distributed to the 
pancreas, as the splenic border runs along its upper border. One of these, 
larger than the rest, follows the course of the pancreatic duct, and is called 
pancreatica magna. 

The Vasa brevia are five or six branches of small size which pass from 
the extremity of the splenic artery and its terminal branches, between the 
layers of the gastro-splenic omentum, to the great end of the stomach, to 
which they are distributed, inosculating with branches of the gastric artery 
and gastro-epiploica sinistra. 

The Gastro-epiploica sinistra appears to be the continuation of the 
«plenic artery ; it passes forwards from left to right, along the great curve 
of the stomach, lying between the layers of the great omentum, and inos- 



312 



SUPERIOR MESENTERIC ARTERY. 



culates with the gastroepiploic^ dextra. It is 
curve of the stomach and to the great omentum. 



distributed to the great 



Fig. 153.* 




The Superior mesenteric artery, the second of the single trunks, 
and next in size to the cceliac axis, arises from the aorta immediately below 
that vessel, and behind the pancreas. It passes forwards between the 
pancreas and transverse duodenum, and descends within the layers of the 
mesentery, to the right iliac fossa, where it terminates, very much dimi- 
nished in size. It forms a curve in its course, the convexity being directed 
towards the left, and the concavity to the right. It is in relation near its 
commencement with the portal vein ; and is accompanied by two veins, 
and the superior mesenteric plexus of nerves. 

The branches of the superior mesenteric artery are — 

Vasa intestini tenuis, 
Ileo-colica, 
Colica dextra, 
Colica media. 

The Vasa intestini tenuis arise from the convexity of the superior me- 
senteric artery. They vary from fifteen to twenty in number, and are dis- 

* The distribution of the branches of the coeliac axis. 1. The liver. 2. Its transverse 
fissure. 3. The gall-bladder. 4. The stomach. 5. The entrance of the oesophagus. 
6. The pylorus. 7. The duodenum, its descending portion. 8. The transverse portion 
of the duodenum. 9. The pancreas. 10. The spleen. 11. The aorta. 12. The cceliac 
axis. 13. The gastric artery. 14. The hepatic artery. 15. Its pyloric branch. 16. The 
gastro-duodenalis. 17. The gastro-epiploica dextra. 18. The pancreatico-duodenalis, 
inosculating with a branch from the superior mesenteric artery. 19. The division of 
the hepatic artery into its right and left branches; the right giving off the cystic branch. 
20. The splenic artery, traced by dotted lines behind the stomach to the spleen. 21. 
The gastro-epiploica sinistra, inosculating along the great curvature of the stomach with 
the gastro-epiploica dextra. 22. The pancreatica magna. 23. The vasa brevia to the 
great end of the stomach, inosculating with branches of the gastric artery. 24. The 
superior mesenteric artery, emerging from between the pancreas and transverse portion 
of the duodenum. 



SUPERIOR MESENTERIC ARTERY. 



313 



tributed to the small intestine from the duodenum to the termination of the 
ileum. In their course between the layers of the mesentery, they form a 
series of arches by the inosculation of their larger branches ; from these 

Fig. 154.* 




are developed secondary arches, and from the latter a third series of arches, 
from which the branches arise which are distributed to the coats of the in- 
testine. From the middle branches a fourth and sometimes even a fifth 
series of arches is produced. By means of these arches a direct commu- 
nication is established between all the branches given off from the convex- 
ity of the superior mesenteric artery ; the superior branches moreover sup- 
ply the pancreas and duodenum, and inosculate with the pancreatico- 
duodenalis ; and the inferior with the ileo-colica. 

The lleo-colic artery is the last branch given off from the concavity of 
the superior mesenteric. It descends to the right iliac fossa, and divides 
into branches which communicate and form arches, from which branches 
are distributed to the termination of the ileum, the caecum, and the com- 
mencement of the colon. This artery inosculates on the one hand with 
the last branches of the vasa intestini tenuis, and on the other with the last 
colica dextra. 

* The course and distribution of the superior mesenteric artery. 1. The descending 
portion of the duodenum. 2. The transverse portion. 3. The pancreas. 4. The jeju- 
num. 5. The ileum. 6. The caecum, from which the appendix vermiformis is seen 
projecting. 7. The ascending colon. 8. The transverse colon. 9. The commencement 
of the descending colon. 10. The superior mesenteric artery. 11. The colica media. 
12. The branch which inosculates with the colica sinistra. 13. The branch of the supe- 
rior mesenteric artery, which inosculates with the pancreatico-duodenalis. 14. The co- 
lica dextra. 15. The ileo-colica. 16, 16. The branches from the convexity of the supe- 
rior mesenteric to the small intestines. 

27 



314 



SPERMATIC ARTERIES. 



The Colica dextra arises from about the middle of the concavity of the 
superior mesenteric, and divides into branches which form arches, and are 
distributed to the ascending colon. Its descending branches inosculate 
with the ileo-colica, and the ascending with the colica media. 

The Colica media arises from the upper part of the concavity of the su- 
perior mesenteric, and passes forwards between the layers of the transverse 
mesocolon, where it forms arches, and is distributed to the transverse 
colon. It inosculates on the right with the colica dextra ; and on the left 
with the colica sinistra, a branch of the inferior mesenteric artery. 

The Spermatic arteries are two small vessels which arise from the 
front of the aorta below the superior mesenteric ; from this origin each 
artery passes obliquely outwards, and accompanies the corresponding 
ureter along the front of the psoas muscle to the border of the pelvis, 
where it is in relation with the external iliac artery. It is then directed 
outwards to the internal abdominal ring, and follows the course of the 

Fig. 155.* 




*The distribution and branches of the inferior mesenteric artery. 1, 1. The superior 
mesenteric artery, with its branches and the small intestines turned over to the right 
side. 2. The caecum and appendix cseci. 3. The ascending colon. 4. The transverse 
colon raised upwards. 5. The descending colon. 6. Its sigmoid flexure. 7. Tde rec- 
tum. 8. The aorta. 9. The inferior mesenteric artery. 10. The colica sinistra, inos- 
culating with, 11, the colica media, a branch of the superior mesenteric artery. 12, 12. 
Sigmoid branches. 13. The superior ha morrhoidal artery. 14. The pancreas. 15. 
The descending portion of the duodenum. 



LUMBAR ARTERIES. 315 

spermatic cord along the spermatic canal and through the scrotum to the 
testicle, to which it is distributed. The right spermatic artery lies in front 
ot the vena cava, and both vessels are accompanied by their corresponding 
veins and by the spermatic plexuses of nerves. 

The spermatic arteries in the female descend into the pelvis and pass 
between the two layers of the broad ligaments of the uterus, to be distri- 
buted to the ovaries, Fallopian tubes, and round ligaments ; along the 
latter they are continued to the inguinal canal and labium at each side. 

They inosculate with the uterine arteries. 

The Inferior mesenteric artery, smaller than the superior, arises 
from the abdominal aorta, about two inches below the origin of that ves- 
sel, and descends between the layers of the left mesocolon, to the left iliac 
fossa, where it divides into three branches : 

Colica sinistra, 

Sigmoidese, 

Superior hsemorrhoidal. 

The Colica sinistra is distributed to the descending colon, and ascends 
to inosculate with the colica media. This is the largest arterial inoscula- 
tion in the body. 

The SigmoidecB are several large branches which are distributed to the 
sigmoid flexure of the descending colon. They form arches, and inoscu- 
late above with the colica sinistra, and below with the superior haemor- 
rhoidal artery. 

The Superior hcemorrhoidal artery is the continuation of the inferior 
mesenteric. It crosses the ureter and common iliac artery of the left side, 
and descends between the two layers of the meso-rectum as far as the 
middle of the rectum to which it is distributed, anastomosing w r ith the 
middle and external hsemorrhoidal arteries. 

The Supra-renal are two small vessels which arise from the aorta im- 
mediately above the renal arteries, and are distributed to the supra-renal 
capsules. They are sometimes branches of the phrenic or of the renal 
arteries. 

The Renal arteries (emulgent) are two large trunks given off* from 
the sides of the aorta immediately below the superior mesenteric artery ; 
the right is longer than the left on account of the position of the aorta, 
and passes behind the vena cava to the kidney of that side.' The left is 
somewhat higher than the right. They divide into several large branches 
previously to entering the kidney, and ramify very minutely in its vascular 
portion. The renal arteries supply several small branches to the supra- 
renal capsules. 

The Lumbar arteries correspond with the intercostals in the chest ; 
they are four or five in number on each side, and curve around the bodies 
of the lumbar vertebrse beneath the psoas muscles, and divide into two 
branches ; one of which passes backwards between the transverse pro- 
cesses, and is distributed to the vertebrae and spinal cord and to the mus- 
cles of the back, whilst the other takes its course behind the quadratus 
lumborum muscle and supplies the abdominal muscles. The first lumbar 



316 COMMON ILIAC ARTERIES. 

artery runs along the lower border of the last rib, and the last along the 
crest of the ilium. In passing between the psoas muscles and the verte- 
brae, they are protected by a series of tendinous arches, which defend 
them and the communicating branches of the sympathetic nerve from 
pressure during the action of the muscle. 

The Sacra media arises from the posterior part of the aorta at its bifur- 
cation, and descends along the middle of the anterior surface of the sacrum 
to the first piece of the coccyx, where it terminates by inosculating with 
the lateral sacral arteries. It distributes branches to the rectum and ante- 
rior sacral nerves, and inosculates on either side with the lateral sacral 
arteries. 

Varieties in the Branches of the Abdominal Aorta. — The phrenic arteries 
are very rarely both derived from the aorta. One or both may be branches 
of the coeliac axis ; one may proceed from the gastric artery, from the 
renal, or from the upper lumbar artery. There are occasionally three or 
more phrenic arteries. The cceliac artery is very variable in length, and 
gives off its branches irregularly. There are sometimes two or even three 
hepatic arteries, one of which may be derived from the gastric or even 
from the superior mesenteric. The colica media is sometimes derived 
from the hepatic artery. The spermatic arteries are very variable, both in 
origin and number. The right spermatic may be a branch of the renal 
artery, and the left a branch of the inferior mesenteric. The supra-renal 
arteries may be derived from the phrenic or renal arteries. The renal 
arteries present several varieties in number ; there may be three or even 
four arteries on one side, and one only on the other. When there are 
several renal arteries on one side, one may arise from the common iliac 
artery, from the front of the aorta near its lower part, or from the internal 
iliac. 

COMMON ILIAC ARTERIES. 

The abdominal aorta divides opposite the fourth lumbar vertebra into 
the two common iliac arteries. Sometimes the bifurcation takes place as 
high as the third, and occasionally as low as the fifth lumbar vertebra. 
The common iliac arteries are about two inches and a half in length ; they 
diverge from the termination of the aorta, and pass downwards and out- 
wards on each side to the margin of the pelvis, opposite the sacro-iliac 
symphysis, where they divide into the internal and external iliac arteries. 
In old persons the common iliac arteries are more or less dilated and 
curved in their course. 

The Right common iliac is somewhat longer than the left, and forms a 
more obtuse angle with the termination of the aorta*^the angle of bifur- 
cation is greater in the female than in the male. 

Relations. — The relations of the two arteries" are different on the two 
sides of the body. The right common iliac is in relation in front with the 
peritoneum, and is crossed at its bifurcation by the ureter. It is in rela- 
tion posteriorly with the two common iliac veins, and externally with the 
psoas magnus. The left is in relation in front with the peritoneum, and 
is crossed by the rectum and superior hemorrhoidal artery, and, at its 
bifurcation, by the ureter. It is in relation behind with the left common 
iliac vein, and externally with the psoas magnus. 



INTERNAL ILIAC ARTERY. 



317 



INTERNAL ILIAC ARTERY. 



The Internal Iliac artery is a short trunk, varying in length from an 
inch to two inches. It descends obliquely to a point opposite the upper 
margin of the great sacro-ischiatic foramen, where it divides into an ante- 
rior and a posterior trunk. 

Fig. 156.* 




Relations. — This artery rests externally on the sacral plexus and on the 
origin of the pyriformis muscle ; posteriorly it is in relation with the in- 
ternal iliac vein, and anteriorly with the ureter. 

Branches. — The branches of the anterior trunk are the — 



Umbilical, 
Middle vesical, 
Middle haemorrhoidal, 

And in the female the — 

Uterine, 

And of the posterior trunk, the — 

Ilio-lumbar, 
Obturator, 



Ischiatic, 
Internal pudic. 



Vaginal. 

Lateral sacral, 
Gluteal. 



,. 



The umbilical artery is the commencement of the fibrous cord into 
which the umbilical artery of the foetus is converted after birth. In after 
life, the cord remains pervious for a short distance, and constitutes the 
umbilical artery of the adult, from which the superior vesical artery is 
given off to the fundus and anterior aspect of the bladder. The cord may 

*The distribution and branches of the iliac arteries. 1. The aorta. 2. The left com- 
mon iliac artery. 3. The external iliac. 4. The epigastric artery. 5. The circumflexa 
ilii. 6. The internal iliac artery. 7. Its anterior trunk. 8. Its posterior trunk. 9. The 
umbilical artery giving off (10) the superior vesical artery. After the origin of this 
branch, the umbilical artery becomes converted into a fibrous cord — the umbilical liga- 
ment. 11. The internal pudic artery passing behind the spine of the ischium (12) and 
lesser sacro-ischiatic ligament. 13. The middle haemorrhoidal artery. 14. The ischiatic 
artery, also passing behind the anterior sacro-ischiatic ligament to escape from the 
pelvis. 15. Its inferior vesical branch. 16. The ilio-lumbar, the first branch of the pos- 
terior trunk (8) ascending to inosculate with the circumflexa ilii artery (5) and form an 
arch along the crest of the ilium. 17. The obturator artery. 18. The lateral sacral. 
19. The gluteal artery escaping from the pelvis through the upper part of the great 
*acro-ischiatic foramen. 20. The sacra media. 21. The right common iliac artery cut 
ihort. 22. The femoral artery. 

27* 



318 ISCHIATIC AND INTERNAL PUDIC ARTERIES. 

be traced forwards by the side of the fundus of the bladder to near its 
apex, whence it ascends by the side of the linea alba and urachus to the 
umbilicus. 

The Middle vesical artery is generally a branch of the umbilical, and 
sometimes of the internal iliac. It is somewhat larger than the superior 
vesical, and is distributed to the posterior part of the body of the bladder, 
the vesiculse seminales, and prostate gland. 

The Middle hemorrhoidal artery is as frequently derived from the 
ischiatic or internal pudic as from the internal iliac. It is of variable size, 
and is distributed to the rectum, base of the bladder, vesiculse seminales, 
and prostate gland, and inosculates with the superior and external hsemor- 
rhoidal arteries. 

The Ischiatic artery is the larger of the two terminal branches of the 
anterior division of the internal iliac. It passes downwards between the 
posterior border of the levator ani and the pyriformis, resting on the sacral 
plexus of nerves, and lying behind the internal pudic artery, to the lower 
border of the great ischiatic notch, where it escapes from the pelvis below 
the pyriformis muscle. It then descends in the space between the tro- 
chanter major and the tuberosity of the ischium in company with the 
ischiatic nerves, and divides into branches. 

Its branches within the pelvis are hceinorrhoidal, which supply the rec- 
tum conjointly with the middle hemorrhoidal, and sometimes take the 
place of that artery, and the inferior vesical, which is distributed to the 
base and neck of the bladder, the vesiculse seminales, and prostate gland. 
The branches externally to the pelvis, are four in number, namely, coccy- 
geal, inferior gluteal, comes nervi ischiatici, and muscular branches. 

The Coccygeal branch pierces the great sacro-ischiatic ligament, and is 
distributed to the coccygeus and levator ani muscles, and to the integu- 
ment around the anus and coccyx. 

The Inferior gluteal branches supply the gluteus maximus muscle. 

The Comes nervi ischiatici is a small but regular branch, which accom- 
panies the great ischiatic nerve to the lower part of the thigh. 

The Muscular branches supply the muscles of the posterior part of the 
hip and thigh, and inosculate with the internal and external circumflex 
arteries, with the obturator, and with the superior perforating artery. 

The Internal pudic artery, the other terminal branch of the anterior 
trunk of the internal iliac, descends in front of the ischiatic artery to the 
lower border of the great ischiatic foramen. It emerges from the pelvis 
through the great sacro-ischiatic foramen below the pyriformis muscle, 
crosses the spine of the ischium, and re-enters the pelvis through the lesser 
sacro-ischiatic foramen ; it then crosses the internal obturator muscle to 
the ramus of the ischium, being situated at about an inch from the margin 
of the tuberosity, and bound down by the obturator fascia ; it next ascends 
the ramus of the ischium, enters between the two layers of the deep peri- 
neal fascia lying along the border of the ramus of the os pubis, and at the 
symphysis pierces the anterior layer of the deep perineal fascia, and, very 
much diminished in size, reaches the dorsum of the penis along which it 
runs, supplying that organ under the name of dorsalis penis. 

Branches. — The branches of the internal pudic artery within the pelvis 
are several small ramuscules to the base of the bladder, the vesiculce semi- 



INTERNAL PUD1C ARTERY. 



319 



nales, and the prostate gland ; and hemorrhoidal branches which supply 
the middle of the rectum, and frequently take the place of the middle 
hemorrhoidal branch of the internal iliac. 

The branches given off externally to the pelvis, are the 

External hemorrhoidal, 
Superficialis perinei, 
Transversal is perinei, 
Arteria bulbosi, 
Arteria corporis cavernosi, 
Arteria dorsalis penis. 

The External hcemorrhoidal arteries are three or four small branches, 
given off by the internal pu die while behind the tuberosity of the ischium. 
They are distributed to the anus, and to the muscles, the fascia, and the 
integument of the anal region of the perineum. 

The Superficial perineal artery is given off near the attachment of the 
cms penis ; it pierces the connecting layer of the superficial and deep 
perineal fascia, and runs forward across the transversus perinei muscle, 
and along the groove between the accelerator urinae and erector penis to 
the septum scroti, upon which it ramifies under the name of arteria septi. 
It distributes branches to the scrotum, and to the perineum in its course 
forwards. One of the latter, larger than the rest, crosses the perineum, 

Fig. 157* 




* The arteries of the perineum; on the right side the superficial arteries are seen, and 
on the left the deep. 1. The penis, consisting of corpus spongiosum and corpus caver- 
nosum. The cms penis on the left side is cut through. 2. The accelerators urinae 
muscles, enclosing the bulbous portion of the corpus spongiosum. 3. The erector peni.% 
spread out upon the crus penis of the right side. 4. The anus, surrounded by the 
sphincter ani muscle. 5. The ramus of the ischium and os pubis. 6. The tuberosity 
of the ischium. 7. The lesser sacro-ischiatic ligament, attached by its small extremity 
to the spine of the ischium. 8. The coccyx. 9. The internal pudic artery, crossing the 
spine of the ischium, and entering the perineum. 10. External hemorrhoidal branches. 
11. The superficialis perinei artery, giving off a small branch, transversahs, perinei, 
upon the transversus perinei muscle. 12. The same artery on the left side cut off. 13. 
The artery of the bulb. 14. The two terminal branches of the internal pudic artery; 
one is seen entering the divided extremity of the crus penis, the artery of the corpus 
cavernosum ; the other, the dorsalis penis, ascends upon the dorsum of the organ. 



320 OBTURATOR ARTERY. 

resting on the transversus perinei muscle, and is named the transversalis 
perinei. 

The Artery of the bulb is given off from the pudic nearly opposite the 
opening for the transmission of the urethra ; it passes almost transversely 
inwards between the two layers of the deep perineal fascia, and pierces 
the anterior layer to enter the corpus spongiosum at its bulbous extremity. 
It is distributed to the corpus spongiosum. 

The Artery of the corpus cavernosum pierces the crus penis, and runs 
forward in the interior of the corpus cavernosum, by the side of the septum 
pectiniforme. It ramifies in the parenchyma of the venous structure of the 
corpus cavernosum. 

The Dorsal artery of the penis ascends between the two crura and sym- 
physis pubis to the dorsum penis, and runs forward, through the suspensory 
ligament, in the groove of the corpus cavernosum to the glans, distributing 
branches in its course to the body of the organ and to the integument. 

The Internal pudic artery in the female is smaller than in the male ; 
its branches, with their distribution are, in principle, the same. The su- 
perficial perineal artery supplies the analogue of the lateral half of the 
scrotum, viz. the greater labium. The artery of the bulb supplies the 
meatus urinarius, and the vestibule ; the artery of the corpus cavernosum, 
the cavernous body of the clitoris, and the arteria dorsalis clitoridis, the 
dorsum of that organ. 

The Uterine and Vaginal arteries of the female are derived either from 
the internal iliac, or from the umbilical, internal pudic, or ischiatic arteries. 
The former are very tortuous in their course, and ascend between the 
layers of the broad ligament, to be distributed to the uterus. The latter 
ramify upon the exterior of the vagina, and supply its mucous membrane. 

Branches of the Posterior Trunk. 

The Ilio-lumbar artery ascends beneath the external iliac vessels and 
psoas muscle, to the posterior part of the crest of the ilium ; where it di- 
vides into two branches, a lumbar branch which supplies the psoas and 
iliacus muscles, and sends a ramuscule through the fifth intervertebral fo- 
ramen to the spinal cord and its membranes ; and an iliac branch which 
passes along the crest of the ilium, distributing branches to the iliacus and 
abdominal muscles, and inosculating with the lumbar and gluteal arteries, 
and with the circumflexa ilii. 

The Obturator artery is exceedingly variable in point of origin ; it 
generally proceeds from the posterior trunk of the internal iliac artery, and 
passes forwards a little below the brim of the pelvis to the upper border 
of the obturator foramen. It there escapes from the pelvis through a ten- 
dinous arch formed by the obturator membrane, and divides into two 
branches ; an internal branch which curves inwards around the bony 
margin of the obturator foramen, between the obturator externus muscle 
md the ramus of the ischium, and distributes branches to the obturator 
muscles, the pectineus, the adductor muscles, and to the organs of gene- 
ration, and inosculates with the internal circumflex artery ; and an external 
branch which pursues its course along the outer margin of the obturator 
foramen to the space between the gemellus inferior and quadratus femoris, 
where it inosculates with the ischiatic artery. In its course backwards it 



EXTERNAL ILIAC ARTERY. 321 

anastomoses with the internal circumflex, and sends a branch through the 
notch in the acetabulum to the hip joint. Within the pelvis the obturator 
artery gives off a branch to the iliacus muscle, and a small ramuscule which 
inosculates with the epigastric artery. 

The Lateral sacral arteries are generally two in number on each 
side ; superior and inferior. The superior passes inwards to the first sacral 
foramen, and is distributed to the contents of the spinal canal, from which 
it escapes by the posterior sacral foramen, and supplies the integument on 
the dorsum of the sacrum. The inferior passes down by the side of the 
anterior sacral foramina to the coccyx ; it first pierces and then rests upon 
the origin of the pyriformis, and sends branches into the sacral canal to 
supply the sacral nerves. Both arteries inosculate with each other and 
with the sacra media. 

The Gluteal artery is the continuation of the posterior trunk of the 
internal iliac : it passes backwards between the lumbo-sacral and first lum- 
bar nerve through the upper part of the great sacro-ischiatic foramen and 
above the pyriformis muscle, and divides into three branches, superficial, 
deep superior, and deep inferior. 

The Superficial branch is directed forwards, between the gluteus maxi- 
mus and medius, and divides into numerous branches, which are distri- 
buted to the upper part of the gluteus maximus and to the integument of 
the gluteal region. 

The Deep superior branch passes along the superior curved line of the 
ilium, between the gluteus medius and minimus to the anterior superior 
spinous process, where it inosculates with the superficial circumflexa ilii 
and external circumflex artery. There are frequently two arteries which 
follow this course. 

The Deep inferior branches are several large arteries which cross the 
gluteus minimus obliquely to the trochanter major, where they inosculate 
with the branches of the external circumflex artery, and send branches 
through the gluteus minimus to supply the capsule of the hip joint. 

Varieties in the Branches of the internal iliac. — The most important of 
the varieties occurring among these branches is the origin of the dorsal 
artery of the penis from the internal iliac or ischiatic. The artery in this 
case passes forwards by the side of the prostate gland, and through the 
upper part of the deep perineal fascia. It would be endangered in the 
operation of lithotomy. The dorsal artery of the penis is sometimes de- 
rived from the obturator, and sometimes from one of the external pudic 
arteries. The artery of the bulb, in its normal course, passes almost 
transversely inwards to the corpus spongiosum. Occasionally, however, 
it is so oblique in its direction as to render its division in lithotomy un- 
avoidable. The obturator artery may be very small or altogether want- 
ing, its place being supplied by a branch from the external iliac or epi- 
gastric. 

external iliac artery. 

The external iliac artery of each side passes obliquely downwards along 
the inner border of the psoas muscle, from opposite the sacro-iliac sym- 
physis to the femoral arch, where it becomes the femoral artery. 

Relations. — It is in relation in front with the spermatic vessels, the 

v 



322 EXTERNAL ILIAC ARTERY. 

peritoneum, and a thin layer of fascia, derived from the iliac fascia, which 
surrounds the artery and vein. At its commencement it is crossed by the 
ureter, and near its termination by the crural branch of the genito-crural 
nerve and the circumflexa ilii vein. Externally it lies against the psoas 
muscle, from which it is separated by the iliac fascia ; and posteriorly it is 
in relation with the external iliac vein, which, at the femoral arch, becomes 
placed to its inner side. The artery is surrounded throughout the whole 
of its course by lymphatic vessels and glands. 

Branches. — Besides several small branches which supply the glands 
surrounding the artery, the external iliac gives off two branches, the — 

Epigastric, 
Circumflexa ilii. 

The Epigastric artery arises from the external iliac near Poupart's liga- 
ment; and passing forwards between the peritoneum and transversalis 
fascia, ascends obliquely to the sheath of the rectus. It enters the sheath 
near its lower third, and passes upwards behind the rectus muscle, to 
which it is distributed, and in the substance of that muscle inosculates, 
near the ensiform cartilage, with the termination of the internal mammary 
artery. It lies internally to the internal abdominal ring and immediately 
above the femoral ring, and is crossed near its origin by the vas deferens 
in the male, and by the round ligament in the female. 

The only branches of the epigastric artery worthy of distinct notice are 
the Cremasteric, which accompanies the spermatic cord and supplies the 
cremaster muscle ; and the ramusculus which inosculates with the obtura- 
tor artery. 

The epigastric artery forms a prominence of the peritoneum which di- 
vides the iliac fossa into an internal and an external portion ; it is from 
the former that direct inguinal hernia issues, and from the latter, oblique 
inguinal hernia. 

The Circumflexa ilii arises from the outer side of the external iliac, 
nearly opposite the epigastric artery. It ascends obliquely along Pou- 
part's ligament, and curving around the crest of the ilium between the 
attachments of the internal oblique and transversalis muscle, inosculates 
with the ilio-lumbar and inferior lumbar artery. Opposite the anterior 
superior spinous process of the ilium, it gives off a large ascending branch 
which passes upwards between the internal oblique and transversalis, and 
divides into numerous branches which supply the abdominal muscles, and 
inosculate with the inferior intercostal and with the lumbar arteries. 

Varieties in the branches of the external iliac. — The epigastric artery not 
unfrequently* gives off the obturator, which descends in contact with the 
external iliac vein, to the obturator foramen. In this situation the artery 
would lie to the outer side of the femoral ring, and would not be endan- 
gered in the operation for dividing the stricture of femoral hernia. But 
occasionally the obturator passes along the free margin of Gimbernat's 
ligament in its course to the obturator foramen, and would completely en- 
circle the neck of the hernial sac, — a position in which it could scarcely 

* The proportion in which high division of the obturator artery from the epigastric 
occurs, is stated to be one in three. In two hundred and fifty subjects examined by 
Cloquet with a view to ascertain how frequently the high division took place, he found 
the obturator arising from the epigastric on both sides one hundred and fifty times ; on 
one side twenty-eight times, and six times it arose from the femoral artery. 



FEMORAL ARTERY. 



323 



escape the knife of the operator. In a preparation in my anatomical col- 
lection, the branch of communication between the epigastric and obturator 
arteries is very much enlarged, and takes this dangerous course. 



FEMORAL ARTERY. 



Emerging from beneath Poupart's ligament, the Fig. 158.* 

external iliac artery enters the thigh and becomes 
the femoral. The femoral artery passes down the 
inner side of the thigh, from Poupart's ligament, 
at a point midway between the anterior superior 
spinous process of the ilium and the symphysis 
pubis, to the opening in the adductor magnus, at 
the junction of the middle with the inferior third 
of the thigh, where it becomes the popliteal artery. 

The femoral artery and vein are enclosed in a 
strong sheath, femoral or crural canal, which is 
formed for the greater part of its extent by aponeu- 
rotic and areolar tissue, and by a process of fascia 
sent inwards from the fascia lata. Near Poupart's 
ligament this sheath is much larger than the vessels 
it contains, and is continuous w 7 ith the fascia trans- 
versalis and iliac fascia. If the sheath be opened 
at this point, the artery will be seen to be situated 
in contact with the outer wall of the sheath. The 
vein lies next the artery, being separated from it 
by a fibrous septum, and between the vein and the 
inner wall of the sheath, and divided from the vein 
by another thin fibrous septum, is a triangular in- 
terval, into which the sac is protruded in femoral 
hernia. This space is occupied in the normal state 
of the parts by loose areolar tissue, and by lympha- 
tic vessels which pierce the inner wall of the sheath 
to make their way to a gland, situated in the femo- 
ral ring. 

Relations. — The upper third of the femoral ar- 
tery is superficial, being covered only by the integument, inguinal glands, 

* A view of the anterior and inner aspect of the thigh, showing the course and 
branches of the femoral artery. 1. The lower part of the aponeurosis of the external 
oblique muscle; its inferior margin is Poupart's ligament. 2. The external abdominal 
ring. 3, 3. The upper and lower part of the sartorius muscle; its middle portion 
having been removed. 4. The rectus. 5. The vastus internus. 6. The patella. 7. 
The iliacus and psoas ; the latter being nearest the artery. 8. The pectineus. 9. The 
adductor longus. 10. The tendinous canal for the femoral artery formed by the adduc- 
tor magnus, and vastus internus muscle. 11. The adductor magnus. 12. The gracilis. 
13. The tendon of the semi-tendinosus. 14. The femoral artery. 15. The superficial 
circumflexa ilii artery taking its course along the line of Poupart's ligament, to the crest 
of the ilium. 2. The superficial epigastric artery. 16. The two external pudic arteries, 
superficial and deep. 17. The profunda artery, giving off 18, its external circumflex 
branch ; and lower down the three perforantes. A small bend of the internal circum- 
flex artery (8) is seen behind the inner margin of the femoral, just below the deep ex- 
ternal pudic artery 19. The anastomotica magna, descending to the knee, upon which 
it ramifies (6). 




324 



FEMORAL ARTERY. 



and by the superficial and deep fasciae. The lower two-thirds are covered 
by the sartorius muscle. To its outer side the artery is first in relation 
with the psoas and iliacus, and then with the vastus internus. Behind it 
rests upon the inner border of the psoas muscle ; it is next separated from 
the pectineus by the femoral vein, profunda vein and artery, and then lies 
on the adductor longus to its termination: near«the lower border of the 
adductor longus, it is placed in an aponeurotic canal, formed by an arch 
of tendinous fibres, thrown from the border of the adductor longus and 
the border of the opening in the adductor magnus, to the side of the 
vastus internus. To its inner side it is in relation at its upper part with 
the femoral vein, and lower down with the pectineus, adductor longus, 
and sartorius. 

The immediate relations of the artery are the femoral vein, and two 
saphenous nerves. The vein at Poupart's ligament lies to the inner side 
of the artery ; but lower down gets altogether behind it, and inclines to its 
outer side. The short saphenous nerve lies to the outer side, and some- 
what upon the sheath for the lower two-thirds of its extent ; and the long 
saphenous nerve is situated within the sheath, and in front of the artery 
for the same extent. 



Plan of the Relations of the Femoral Artery. 



Front. 



Inner Side. 
Femoral vein, 
Pectineus, 
Adductor longus, 
Sartorius. 



Fascia lata, 

Saphenous nerves, 

Sartorius, 

Arch of the tendinous canal. 




Femoral artery. 




Outer Side. 

Psoas, 
Iliacus, 
Vastus internus 


Behind. 

Psoas muscle, 
Femoral vein, 
Adductor longus. 







Branches. — The branches of the Femoral Artery are the — 

Superficial circumflexa ilii, 
Superficial epigastric, 
Superficial external pudic, 
Deep external pudic, 

C External circumflex, 
Profunda < Internal circumflex, 

( Three perforating, 
Muscular, 
Anastomotica magna. 

The Superficial circumflexa ilii artery arises from the femoral, imme- 
diately below Poupart's ligament, pierces the fascia lata, and passes ob- 



PROFUNDA ARTERY. 



325 



liquely outwards towards the crest of the ilium. It supplies the integument 
of the groin, the superficial fascia, and inguinal glands. 

The Superficial epigastric arises from the femoral, immediately below 
Poupart's ligament, pierces the fascia lata, and ascends obliquely towards 
the umbilicus between the two layers of superficial fascia. It distributes 
branches to the inguinal glands and integument, and inosculates with 
branches of the deep epigastric and internal mammary artery. 

The Superficial external pudic arises near the superficial epigastric 
artery ; it pierces the fascia lata, at the saphenous opening, and passes 
transversely inwards, crossing the spermatic cord, to be distributed to the 
integument of the penis and scrotum in the male, and to the labia in the 
female. 

The Deep external pudic arises from the femoral, a little lower down 
than the preceding : it crosses the femoral vein immediately below the 
termination of the internal saphenous vein, and piercing the pubic portion 
of the fascia lata, passes beneath that fascia to the inner border of the 
thigh, where it again pierces the fascia ; having become superficial, it is 
distributed to the integument of the scrotum and perineum. 



The Profunda femoris arises from the femoral artery at two inches 
below Poupart's ligament : it passes downwards and backwards and a 
little outwards, behind the adductor longus muscle, pierces the adductor 
magnus, and is distributed to the flexor muscles on the posterior part of 
the thigh. 

Relations. — In its course downwards it rests successively upon the pecti- 
neus, the conjoined tendon of the psoas and iliacus, adductor brevis, and 
adductor magnus muscles. To its outer side the tendinous insertion of 
the vastus internus muscle intervenes between it and the femur ; on its 
inner side it is in relation with the pectineus, adductor brevis, and adduc- 
tor magnus ; and in front it is separated from the femoral artery, above by 
the profunda vein and femoral vein, and below by the adductor longus 
muscle. 

Plan of the Relations of the Profunda Jlrtery. 

In Front. 

Profunda vein, 
Adductor longus. 



Inner Side. 

Pectineus, 
Adductor brevis, 
Adductor magnus. 



Profunda artery. 



Outer Side. 

Psoas and iliacus, 
Vastus internus, 
Femur. 



Behind. 

Pectineus, 

Tendon of psoas and iliacus, 
Adductor brevis, 
Adductor magnus. 

Branches. — The branches of the profunda artery are, the external cir- 
cumflex, internal circumflex, and three perforating arteries. 

The External circumflex artery passes obliquely outwards between the 
. 28 



326 POPLITEAL ARTERY. 

divisions of the crural nerve, then between the rectus and crureus muscle, 
and divides into three branches ; ascending, which inosculates with the 
terminal branches of the gluteal artery ; descending, which inosculates with 
the superior external articular artery ; and middle, which continues the 
original course of the artery around the thigh, and anastomoses with branches 
of the ischiadic, internal circumflex, and superior perforating artery. It 
supplies the muscles on the anterior and outer side of the thigh. 

The Internal circumflex artery is larger than the external ; it winds 
around the inner side of the neck of the femur, passing between the pecti- 
neus and psoas, and along the border of the external obturator muscle, to 
the space between the quadratus femoris and upper border of the adductor 
magnus, where it anastomoses with the ischiatic, external circumflex, and 
superior perforating artery. It supplies the muscles of the upper and inner 
side of the thigh, anastomosing with the obturator artery, and sends a small 
branch through the notch in the acetabulum into the hip joint. 

The Superior perforating artery passes backwards between the pectineus 
and adductor brevis, pierces the adductor magnus near the femur, and 
is distributed to the posterior muscles of the thigh ; inosculating freely 
with the circumflex and ischiatic arteries, and with the branches of the 
middle perforating artery. 

The Middle perforating artery pierces the tendons of the adductor brevis 
and magnus, and is distributed like the superior ; inosculating with the 
superior and inferior perforantes. This branch frequently give£ off the 
nutritious artery of the femur. m 

The Inferior perforating artery is given off below the adductor brevis, 
and pierces the tendon of the adductor magnus, supplying it and the flexor 
muscles, and inosculating with the middle perforating artery above, and 
with the articular branches of the popliteal below. It is through the me- 
dium of these branches that the collateral circulation is maintained in the 
limb after ligature of the femoral artery. 

The Muscular branches are given off by the femoral artery throughout 
the whole of its course. They supply the muscles in immediate proximity 
with the artery, particularly those of the anterior aspect of the thigh. One 
of these branches, larger than the rest, arises from the femoral immediately 
below the origin of the profunda, and passing outwards between the rectus 
and sartorius divides into branches which are distributed to all the muscles 
of the anterior aspect of the thigh. This may be named the superior mus- 
cular artery. 

The Jlnastomotica magna arises from the femoral while in the tendinous 
canal formed by the adductors and vastus internus. It runs along the ten- 
don of the adductor magnus to the inner condyle, and inosculates with the 
superior internal articular artery ; some of its branches are distributed to 
the vastus internus muscle and to the crureus, and terminate by anasto- 
mosing with the branches of the external circumflex and superior external 
articular artery. 

POPLITEAL ARTERY. 

The popliteal artery (Fig. 160) commences from the termination of the 
femoral at the opening in the adductor magnus muscle, and passes obliquely 
outwards through the middle of the popliteal space to the lower border of 
the popliteus muscle, where it divides into the anterior and posterior tibial 
artery. 



POPLITEAL ARTERY. 



327 



Relations. — In its course downwards it rests first on the femur, then on 
the posterior ligament of the knee joint, then on the fascia, covering the 
popliteus muscle. Superficially it is in relation with the semi-membranosus 
muscle, next with a quantity of fat which separates it from the deep fascia, 
and near its termination with the gastrocnemius plantaris, and soleus ; 
superficial and external to it is the popliteal vein, and still more superficial 
and externa], the popliteal nerve. By its inner side it is in relation with the 
semi-membranosus, internal condyle of the femur, and inner head of the 
gastrocnemius ; and by its outer side with the biceps, external condyle of 
the femur, the outer head of the gastrocnemius, the plantaris and the 
soleus. 

Plan of the Relations of the Popliteal Artery. 

Superficially. 

Semi-membranosus, 
Popliteal nerve, 
Popliteal vein, 
Gastrocnemius, 
Plantaris, 
Soleus. 



Inner Side. 

Semi-membranosus, 
Internal condyle, 
Gastrocnemius. 




Outer Side. 

Biceps, 

External condyle, 

Gastrocnemius, 

Plantaris, 

Soleus. 



Deeply. 

Femur, 

Ligamentum posticum Winslowii, 

Popliteal fascia. 

Branches. — The branches of the popliteal artery are the 

Superior external articular, 
Superior internal articular, 
Azygos articular, 
Inferior external articular, 
Inferior internal articular, 
Sural. 

The Superior articular arteries, external and internal, wind around the 
femur, immediately above the condyles, to the front of the knee joint, 
anastomosing w r ith each other, with the external circumflex, the anasto- 
motica magna, the inferior articular, and the recurrent of the anterior 
tibial. The external passes beneath the tendon of the biceps, and the 
internal through an arched opening beneath the tendon of the adductor 
magnus. They supply the knee joint and the lower part of the femur. 

The Azygos articular artery pierces the posterior ligament of the joint, 
the ligamentum posticum Winslowii, and supplies the synovial membrane 
in its interior. There are, frequently, several posterior articular arteries. 

The Inferior articular arteries wind around the head of the tibia imme- 
diately below the joint, and anastomose with each other, the superior 
articular arteries, and the recurrent of the anterior tibial. The external 
passes beneath the two external lateral ligaments of the joint, and the in- 



328 



ANTERIOR TIBIAL ARTERY. 



Fig. 159.* 




ternal beneath the internal lateral ligament. They 
supply the knee joint and the heads of the tibia and 
fibula. 

The Sural arteries (sura, the calf) are two large 
muscular branches, which are distributed to the two 
heads of the gastrocnemius muscle. 

ANTERIOB TIBIAL ARTERY. 

The anterior tibial artery passes forwards between 
the two heads of the tibialis posticus muscle, and 
through the opening in the upper part of the inter- 
osseous membrane, to the anterior tibial region. It 
then runs down the anterior aspect of the leg to the 
ankle joint, where it becomes the dorsalis pedis. 

Relations. — In its course downwards it rests upon 
the interosseous membrane (to which it is connected 
by a little tendinous arch which is thrown across it), 
the lower part of the tibia, and the anterior ligament 
of the joint. In the upper third of its course it is 
situated between the tibialis anticus and extensor 
longus digitorum, lower down between the tibialis 
anticus and extensor proprius pollicis ; and just be- 
fore it reaches the ankle it is crossed by the tendon 
of the extensor proprius pollicis, and becomes placed 
between that tendon and the tendons of the extensor 
longus digitorum. Its immediate relations are the 
venae comites and the anterior tibial nerve, which 
latter lies at first to its outer side, and at about the 
middle of the leg becomes placed superficially to 
the artery. 



Plan of the Relations of the Anterior Tibial Artery. 

Front. 

Deep fascia, 
Tibialis anticus, 
Extensor longus digitorum, 
Extensor proprius pollicis, 
Anterior tibial nerve. 



Inner Side. 
Tibialis anticus, 
Tendon of the ex- 
tensor proprius 
pollicis. 



Anterior Tibial Artery. 



Outer Side. 

Anterior tibial nerve, 
Extensor longus digitorum, 
Extensor proprius pollicis, 
Tendons of the extensor 
longus digitorum. 



Behind. 
Interosseous membrane, 
Tibia (lower fourth), 
Ankle joint. 
.. • 
♦The anterior aspect of the leg and foot, showing the anterior tibial and dorsalis 
pedis arteries, with their branches. 1. The tendon of insertion of the quadriceps ex- 
tensor muscle. 2. The insertion of the ligamentum patellae into the lower border of the 
patella. 3. The tibia. 4. The extensor proprius pollicis muscle. 5. The extensor lon- 
gus digitorum. 6. The peronei muscles. 7. The inner belly of the gastrocnemius and 



DORSALIS PEDIS ARTERY. 



329 



Branches. — The branches of the Anterior Tibial Artery are the — 

Recurrent, 
Muscular, 
External malleolar, 
Internal malleolar. 

The Recurrent branch passes upwards beneath the origin of the tibialis 
anticus muscle to the front of the knee joint, upon which it is distributed, 
anastomosing with the articular arteries. 

The Muscular branches are very numerous, they supply the muscles of 
the anterior tibial region. 

The Malleolar arteries are distributed to the ankle joint ; the external 
passing beneath the tendons of the extensor longus digitorum and pero- 
neus tertius, inosculates with the anterior peroneal artery and with the 
branches of the dorsalis pedis ; the internal, beneath the tendons of the 
extensor proprius pollicis and tibialis anticus, inosculates with branches 
of the posterior tibial and internal plantar artery. They supply branches 
to the ankle joint. 

The Dorsalis pedis artery is continued forward along the tibial side 
of the dorsum of the foot, from the ankle to the base of the metatarsal bone 
of the great toe, where it divides into two branches, the dorsalis hallucis 
and communicating. 

Relations. — The dorsalis pedis is situated along the outer border of the 
tendon of the extensor proprius pollicis ; on its fibular side is the inner- 
most tendon of the extensor longus digitorum, and near its termination it 
is crossed by the inner tendon of the extensor brevis digitorum. It is ac- 
companied by venae comites, and has the continuation of the anterior tibial 
nerve to its outer side. 

Plan of the Relations of the Dorsalis Pedis Artery. 

In Front. 

Integument, 

Deep fascia, 

Inner tendon of the extensor 

brevis digitorum. 



Inner Side. 

Tendon of the ex- 
tensor proprius 
pollicis. 



Dorsalis Pedis Artery. 



Outer Side. 

Fendon of the extensor 

longus digitorum, 
Border of the extensor 

brevis digitorum muscle. 



Behind. 

Bones of the tarsus, with 
their ligaments. 

the soleus. 8. The annular ligament beneath which the extensor tendons and the an- 
terior tibial artery pass into the dorsum of the foot. 9. The anterior tibial artery. 10. 
Its recurrent branch inosculating with (2) the inferior articular, and (1) the superior 
articular arteries, branches of the popliteal. 11. The internal malleolar artery. 17. 
The external malleolar inosculating with the anterior peroneal artery 12. 13. The dor- 
salis pedis artery. 14. The tarsea and metatarsea arteries; the tarsea is nearest the 
ankle, the metatarsea is seen giving off the interosseae. 15. The dorsalis hallucis artery. 
16. The communicating branch. 

28* 



330 



POSTERIOR TIBIAL ARTERY. 



Fig. 160.' 



Branches. — The branches of this artery are the — 

Tarsea, 

Metatarsea , — interosseae, 

Dorsalis hallucis, — collateral digital, 

Communicating. 

The Tarsea arches transversely across the tarsus, beneath the extensor 
brevis digitorum muscle, and supplies the articulations of the tarsal bones 
and the outer side of the foot ; it anastomoses with the external malleolar, 
the peroneal arteries, and the external plantar. 

The Metatarsea forms an arch across the base of the 
metatarsal bones, and supplies the outer side of the 
foot ; anastomosing with the tarsea and with the exter- 
nal plantar artery. The metatarsea gives off three 
branches, the interossece, which pass forward upon the 
dorsal interossei muscles, and divide into two collateral 
branches for adjoining toes. At their commencement 
these interosseous branches receive the posterior per- 
forating arteries from the plantar arch, and opposite the 
heads of the metatarsal bones they are joined by the 
anterior perforating branches from the digital arteries. 

The Dorsalis hallucis runs forward upon the first dor- 
sal interosseous m.uscle, and at the base of the first 
phalanx divides into two branches, one of whieh passes 
inwards beneath the tendon of the extensor proprius 
pollicis, and is distributed to the inner border of the 
great toe, while the other bifurcates for the supply of 
the adjacent sides of the great and second toe. 

The Communicating artery passes into the sole of the 
foot between the two heads of the first dorsal interos- 
seous muscle, and inosculates with the termination of 
the external plantar artery. 

Besides the preceding, numerous branches are dis- 
tributed to the bones and articulations of the foot, par- 
ticularly along the inner border of the latter. 



POSTERIOR TIBIAL ARTERY. 

The posterior tibial artery passes obliquely down- 
wards along the tibial side of the leg from the lower 

* A posterior view of the leg, showing the popliteal and posterior tibial artery. 1. 
The tendons forming the inner hamstring. 2. The tendon of the biceps forming the 
outer hamstring. 3. The popliteus muscle. 4. The flexor longus digitorum. 5. The 
tibialis posticus. 6. The fibula; immediately below the figure is the origin of the flexor 
)ongus pollicis; the muscle has been removed in order to expose the peroneal artery. 
7. The peronei muscles, longus and brevis. 8. The lower part of the flexor longus 
pollicis muscle with its tendon. 9. The popliteal artery giving off its articular and 
muscular branches; the two superior articular are seen in the upper part of the popli- 
teal space passing above the two heads of the gastrocnemius muscle, which are cut 
through near their origin. The two inferior are in relation with the popliteus muscle. 
10. The anterior tibial artery passing through the angular interspace between the two 
heads of the tibialis posticus muscle. 11. The posterior tibial artery. V2. The relative 
position of the tendons and artery at the inner ankle from within outwards, previously 
to their passing beneath the internal annular ligament. 13. The peroneal artery, dividing. 
a little below the number, into two branches ; the anterior peroneal is seen piercing the 
interosseous membrane. 14. The posterior peroneal. 



POSTERIOR TIBIAL AND PERONEAL ARTERIES. 



331 



border of the popliteus muscle to the concavity of the os calcis, where it 
divides into the internal and external plantar artery. 

Relations. — In its course downwards it lies first upon the tibialis posti- 
next on the flexor longus digitorum, and then on the tibia ; it is 



cus 



covered in by the intermuscular fascia which separates it above from the 
soleus, and below from the deep fascia of the leg and the integument. It 
is accompanied by its vena? comites, and by the posterior tibial nerve, 
which latter lies at first to its outer side, then superficially to it, and again 
to its outer side. 

Plan of the Relations of the Posterior Tibial Artery. 

Superficially. 

Soleus, 
Deep fascia, 
The intermuscular fascia. 



Inner Side. 
Vein. 



Posterior Tibial 
Artery. 



Outer Side. 

Posterior tibial nerve, 
Vein. 



Deeply. 

Tibialis posticus, 
Flexor longus digitorum, 
Tibia. 

Branches. — The branches of the posterior tibial artery are the- 



Peroneal, 

Nutritious, 

Muscular, 



Internal calcanean, 
Internal plantar, 
External plantar. 



The Peroneal artery is given off from the posterior tibial at about tw r o 
inches below the low T er border of the popliteus muscle ; it is nearly as 
large as the anterior tibial artery, and passes obliquely outwards to the 
fibula. It then runs downwards along the inner border of the fibula to 
its lower third, where it divides into the anterior and posterior peroneal 
artery. 

Relations. — The peroneal artery rests upon the tibialis posticus muscle, 
and is covered in by the soleus, the intermuscular fascia, and the flexor 
jongus pollicis, having the fibula to its outer side. 



Plan of the Relations of the Peroneal Artery. 

In Front. 

Soleus, 

Intermuscular fascia, 
Flexor longus pollicis. 



Peroneal Artery. 



Behind. 
Tibialis posticus. 



Outer Side. 
Fibula. 



332 



PLANTAR ARTERIES. 



Branches. — The branches of the peroneal artery are, muscular to the 
neighbouring muscles, particularly to the soleus, and the two terminal 
branches anterior and posterior peroneal. 

The Anterior peroneal pierces the interosseous membrane at the lower 
third of the leg, and is distributed on the front of the outer malleolus, 
anastomosing with the external malleolar and tarsal artery. This branch 
is very variable in size. 

The Posterior peroneal continues onwards along the posterior aspect of 
the outer malleolus to the side of the os calcis, to which and to the mus- 
cles arising from it, it distributes external calcanean branches. It anasto- 
moses with the anterior peroneal, tarsal, external plantar, and posterior 
tibial artery. 

The Nutritious artery of the tibia arises from the trunk of the tibial, 
frequently above the origin of the peroneal, and proceeds to the nutritious 
canal, which it traverses obliquely from below upwards. 

The Muscular branches of the posterior tibial artery are distributed to 
the soleus and to the deep muscles on the posterior aspect of the leg. One 
of these branches is deserving of notice, a recurrent branch, which arises 
from the posterior tibial above the origin of the peroneal artery, pierces 
the soleus, and is distributed upon the inner side of the head of the tibia, 
anastomosing with the inferior internal articular. 

The Internal calcanean branches, three or four in number, proceed from 
the posterior tibial artery immediately before its division ; they are distri- 
buted to the inner side of the os calcis, to the integument, and to the 
muscles which arise from its inner tuberosity, and they anastomose with 
the external calcanean branches, and with all the neighbouring arteries. 



Fig. 161* 



PLANTAR ARTERIES. 

The Internal plantar artery proceeds from the bifur- 
cation of the posterior tibial at the inner malleolus, 
and passes along the inner border of the foot between 
the abductor pollicis and flexor brevis digitorum mus- 
cles, supplying the inner border of the foot and great 
toe. 

The External plantar artery, much larger than the 
internal, passes obliquely outwards between the first 
and second layers of the plantar muscles, to the fifth 
metatarsal space. It then turns horizontally inwards 
between the second and third layers, to the first meta- 
tarsal space, where it inosculates with the communi- 
cating branch from the dorsalis pedis. The horizontal 
portion of the artery describes a slight curve, having 
the convexity forwards ; this is the plantar arch. 

Branches. — The branches of the external plantar 
artery are the — 

Muscular, 

Articular, 

Digital, — anterior perforating, 

Posterior perforating. 

* The arteries of the sole of the foot ; the first and a part of the second layer of mus- 
cles having been removed. 1. The under and posterior part of the os calcis; to which 
the origins of the first layer of muscles remain attached. 2. The musculus accessorius. 




VARIETIES IN THE ARTERIES OF THE LOWER EXTREMITY. 333 

The Muscular branches are distributed to the muscles in the sole of the 
foot. 

The Articular branches supply the ligaments of the articulations of the 
tarsus, and their synovial membranes. 

The Digital branches are four in number : the first is distributed to the 
outer side of the little toe ; the three others pass forwards to the cleft be- 
tween the toes, and divide into collateral branches, which supply the 
adjacent sides of the three external toes, and the outer side of the second. 
At the bifurcation of the toes, a small branch is sent upwards from each 
digital artery, to inosculate with the interosseous branches of the metatar- 
sea ; these are the anterior perforating arteries. 

The Posterior perforating are three small branches which pass upwards 
between the heads of the three external dorsal interossei muscles to inos- 
culate with the arch formed by the metatarsea artery. 

Varieties in the Arteries of the Lower Extremity. — The femoral artery 
occasionally divides at Poupart's ligament into two branches, and some- 
times into three ; the former is an instance of the high division of the pro- 
funda artery ; and in a case of the latter kind which occurred during my 
dissections, the branches were the profunda, the superficial femoral, and 
the internal circumflex artery. Dr. Quain, in his " Elements of Anatomy," 
records an instance of a high division of the femoral artery, in which the 
two vessels became again united in the popliteal region. The point of 
origin of the profunda artery varies considerably in different subjects, 
being sometimes nearer to and sometimes farther from Poupart's ligament, 
but more frequently the former. The branches of the popliteal artery are 
very liable to variety in size ; and in all these cases the compensating 
principle, so constant in the vascular system, is strikingly manifested. 
When the anterior tibial is of small size, the peroneal is large ; and, in 
place of dividing into two terminal branches at the lower third of the leg, 
descends to the lower part of the interosseous membrane, and emerges 
upon the front of the ankle, to supply the dorsum of the foot : or the pos- 
terior tibial and plantar arteries are large, and the external plantar is con- 
tinued between the heads of the first dorsal interosseous muscle, to be 
distributed to the dorsal surface of the foot. Sometimes the posterior 
tibial artery is small and thread-like ; and the peroneal, after descending 
to the ankle, curves inwards to the inner malleolus, and divides into the 
two plantar arteries. If, in this case, the posterior tibial be sufficiently 
large to reach the ankle, it inosculates with the peroneal previously to its 
division. The internal plantar artery sometimes takes the distribution of 
the external plantar, which is short and diminutive, and the latter not un- 
frequently replaces a deficient dorsalis pedis. 

The varieties of arteries are interesting in the practical application of a 
knowledge of their principal forms to surgical operations ; in their tran- 
scendental anatomy, as illustrating the normal type of distribution in ani- 
mals ; or, in many cases, as diverticula permitted by Nature, to teach her 
observers two important principles :— -first, in respect to herself, that, how- 
ever in her means she may indulge in change, the end is never overlooked, 
and a limb is as surely supplied by a leash of arteries, various in their 

3. The long flexor tendons. 4. The tendon of the peroneus longus. 5. The termination 
of the posterior tibial artery. 6. The internal plantar. 7. The external plantar artery. 
8. The plantar arch giving off four digital branches, which pass forwards on the inter- 
ossei muscles. Three of these arteries are seen dividing, near the heads of the meta- 
tarsal bones, into collateral branches for adjoining toes. 



334 



OF THE VEINS. 



course, as by those which we are pleased to consider normal in distribu- 
tion ; and, secondly, with regard to us, that we should ever be keenly alive 
to what is passing beneath our observation, and ever ready in the most 
serious operation to deviate from our course and avoid — or give eyes to 
our knife, that it may see, — the concealed dangers which it is our pride 
to be able to contend with and vanquish. 

PULMONARY ARTERY. 

The pulmonary artery arises from the left side of the base of the right 
ventricle in front of the origin of the aorta, and ascends obliquely to the 
under surface of the arch of the aorta, where it divides into the right and 
left pulmonary arteries. In its course upwards and backwards it inclines 
to the left side, crossing the commencement of the aorta, and is connected 
to the under surface of the arch by a thick and impervious cord, the re- 
mains of the ductus arteriosus. 

Relations. — It is enclosed for one-half of its extent by the pericardium, 
and receives the attachment of the fibrous portion of that membrane by its 
upper portion. Behind, it rests against the ascending aorta ; on either 
side is the appendix of the corresponding auricle with a coronary artery ; 
and above, the cardiac ganglion and the remains of the ductus arteriosus. 

The Right pulmonary artery passes beneath the arch and behind the 
ascending aorta, and in the root of the lungs divides into three branches 
for the three lobes. 

The Left pulmonary artery, rather larger than the right, passes in front 
of the descending aorta, to the root of the left lung, to which it is distri- 
buted. These arteries divide and subdivide in the structure of the lungs, 
and terminate in capillary vessels which form a network around the air- 
passages and cells, and become continuous with the radicles of the pul- 
monary veins. 

Relations. — In the root of the right lung, examined from above down- 
wards, the pulmonary artery is situated between the bronchus and pulmo- 
nary veins, the former being above, the latter below ; while in the left 
lung the artery is the highest, next the bronchus, and then the veins. On 
both sides, from before backwards, the artery is situated between the veins 
and bronchi, the former being in front, and the latter behind. 



CHAPTER VII. 



OF THE VEINS. 



The veins are the vessels which return the blood to the auricles of the 
heart, after it has been circulated by the arteries through the various tis- 
sues of the body. They are much thinner in structure tfran the arteries, 
so that when emptied of their blood they become flattened and collapsed. 
The veins of the systemic circulation convey the dark-coloured and im- 
pure or venous blood from the capillary system to the right auricle of the 
heart, and they are found after death to be more or less distended with 
that fluid. The veins of the pulmonary circulation resemble the arteries 
of the systemic circulation in containing during life the pure or arterial 



STRUCTURE OF VEINS. 

blood, which they transmit from the capillaries of the lun^ 
auricle. 

The veins commence by minute radicles in the capillaries which. are 
everywhere distributed through the textures of the body, and converge to 
constitute larger and larger branches, till they terminate in the main trunks 
which convey the venous blood directly to the heart. In diameter they 
are larger than the arteries, and, like those vessels, their combined areas 
would constitute an imaginary cone, whereof the apex is placed at the 
heart, and the base at the surface of the body. It follows from this ar- 
rangement, that the blood in returning to the heart is passing from a larger 
into a smaller channel, and therefore that it increases in rapidity during 
its course. 

Veins admit of a threefold division into, superficial, deep, and sinuses. 

The Superficial veins return the blood from the integument and super- 
ficial structures, and take their course between the layers of the superficial 
fascia; they then pierce the deep fascia in the most convenient and pro- 
tected situations, and terminate in the deep veins. They are unaccompa- 
nied by arteries, and are the vessels usually selected for venesection. 

The Deep veins are situated among the deeper structures of the body, 
and generally in relation with the arteries ; in the limbs they are enclosed 
in the same sheath with those vessels, and they return the venous blood 
from the capillaries of the deep tissues. In company with all the smaller, 
and also with the secondary arteries, as the brachial, radial, and ulnar in 
the upper, and the tibial and peroneal in the lower extremity, there are 
two veins, placed one on each side of the artery, and named vents comites. 
The larger arteries, as the axillary, subclavian, carotid, popliteal, femoral, 
&c, are accompanied by a single venous trunk. Sinuses differ from veins 
in their structure ; and also in their mode of distribution, being confined 
to especial organs and situated within their substance. The principal 
venous sinuses are those of the dura mater, the diploe, the cancellous 
structure of bones, and the uterus. 

The communications between veins are even more frequent than those 
of arteries, and they take place between the larger as well as among the 
smaller vessels ; the venae comites communicate with each other very fre- 
quently in their course, by means of short transverse branches which pass 
across from one to the other. These communications are strikingly ex- 
hibited in the frequent inosculations of the spinal veins, and in the various 
venous plexuses, as the spermatic plexus, vesical plexus, &c. The office 
of these inosculations is very apparent, as tending to obviate the obstruc- 
tions to which the veins are particularly liable from the thinness of their 
coats, and from their inability to overcome much impediment by the force 
of their current. 

Veins, like arteries, are composed of three coats, external or areolo- 
fibrous, middle or fibrous, and internal or serous. The external coat is 
firm and strong, and resembles that of arteries. The middle coat consists 
of two layers, an outer layer of contractile fibrous tissue disposed in a cir- 
cular direction around the vessel, and an inner layer of organic muscular 
fibres arranged longitudinally. This latter resembles the inner layer of 
the middle coat of arteries, but is somewhat thicker ; it is not unfrequently 
hypertrophied. The internal coat, as in arteries, consists of a striated or 
fenestrated layer, and a layer of epithelium ; it is continuous with the in- 
ternal coat of arteries through the medium of the lining membrane of the 



336 



VEINS OF THE HEAD AND NECK. 



heart on the one hand, and through the capillary vessels on the other. 
The differences in structure, therefore, between arteries and veins, relate 
to the difference of thickness of their component layers, and to the absence 
of the elastic coat in the latter. Moreover, another difference occurs in 
the presence of valves. The valves of veins are composed of a thin layer 
of fibrous membrane, lined upon its two surfaces by epithelium. The 
segments or flaps of the valves of veins are semilunar in form and arranged 
in pairs, one upon either side of the vessel ; in some instances there is but 
a single flap, which has a spiral direction, and occasionally there are three. 
The free border of the valvular flaps is concave, and directed forwards, 
so that while the current of blood is permitted to flow freely towards the 
heart, the valves are distended and the current intercepted if the stream 
become retrograde in its course. Upon the cardiac side of each valve the 
vein is expanded into two pouches (sinuses), corresponding with the flaps 
of the valves, which give to the distended or injected vein a knotted ap- 
pearance. The valves are most numerous in the veins of the extremities, 
particularly in the deeper veins, and they are generally absent in the very 
small veins, and in the veins of the viscera, as in the portal and cerebral 
veins : they are also absent in the large trunks, as in the venae cavae, vense 
azygos, innominatae, and iliac veins. 

Sinuses are venous channels, excavated in the structure of an organ, 
and lined by the internal coat of the veins ; of this structure are the sinuses 
of the dura mater, whose external covering is the fibrous tissue of the 
membrane, and the internal, the serous layer of the veins. The external 
investment of the sinuses of the uterus is the tissue of that organ ; and that 
of the bones, the lining membrane of the cells and canals. 

Veins, like arteries, are supplied with nutritious vessels, the vasa vaso- 
runa ; and it is to be presumed that nervous filaments are distributed in 
their coats. 

I shall describe the veins according to the primary division of the body , 
taking first, those of the head and neck ; next, those of the upper extre- 
mity ; then, those of the lower extremity ; and lastly, the veins of the 
trunk. 

VEINS OF THE HEAD AND NECK. 

The veins of the head and neck may be arranged into three groups, viz. 
1. Veins of the exterior of the head. 2. Veins of the diploe and interior 
of the cranium. 3. Veins of the neck. 

The veins of the exterior of the head are the — 

Facial, 

Internal maxillary, 

Temporal, 

Temporo-maxillary, 

Posterior auricular, 

Occipital. 

The Facial vein commences on the anterior part of the skull in a venous 
plexus, formed by the communications of the branches of the temporal, 
and descends along the middle line of the forehead, under the name of 
frontal vein, to the root of the npse, where it is connected with its fellow 
of the opposite side by a communicating trunk which constitutes the nasal 
arch. There are usually two frontal veins, which communicate by a trans- 



VEINS OF THE DIPLOE. 337 

verse inosculation ; but sometimes the vein is single and bifurcates at the 
root of the nose, into the two angular veins. From the nasal arch, the 
frontal is continued downwards by the side of the root of the nose, under 
the name of the angular vein ; it then passes beneath the zygomatic mus- 
cles and becomes the facial vein, and descends along the anterior border 
of the masseter muscle, crossing the body of the lower jaw, by the side of 
the facial artery, to the submaxillary gland, and from thence to the inter- 
nal jugular vein in which it terminates. 

The branches which the facial vein receives in its course are, the supra- 
orbital, which joins the frontal vein ; the dorsal veins of the nose which 
terminate in the nasal arch ; the ophthalmic, which communicates with 
the angular vein ; the palpebral and nasal, which open into the angular 
vein ; a considerable trunk, the alveolar, which returns the blood from the 
spheno-maxillary fossa, from the infra-orbital, palatine, vidian, and spheno- 
palatine veins, and joins the facial beneath the zygomatic process of the 
superior maxillary bone, and the veins corresponding with the branches 
of the facial artery. 

The Internal maxillary vein receives the branches from the zygomatic 
and pterygoid fossae ; these are so numerous and communicate so freely as 
to constitute a pterygoid plexus. Passing backwards behind the neck of 
the lower jaw, the internal maxillary joins w T ith the temporal vein, and the 
common trunk resulting from this union constitutes the temporo-maxillary 
vein. s 

The Temporal vein commences on the vertex of the head by a plexiform 
network which is continuous with the frontal, the temporal, auricular, and 
occipital veins. The ramifications of this plexus form an anterior and a pos- 
terior branch which unite immediately above the zygoma ; the trunk is here 
joined by another large vein, the middle temporal, which collects the blood 
from the temporal muscle, and around the outer segment of the orbit, and 
pierces the temporal fascia near the root of the zygoma. The temporal 
vein then descends between the meatus auditorius externus and the con- 
dyle of the lower jaw, and unites with the internal maxillary vein, to form 
the temporo-maxillary. 

The Temporo-maxillary vein formed by the union of the temporal and 
internal maxillary, passes downwards in the substance of the parotid gland 
to its lower border, where it becomes the external jugular vein. It receives 
in its course the anterior auricular, masseteric, transverse facial, and paro- 
tid veins, and near its termination is joined by the posterior auricular vein. 

The Posterior auricular vein communicates with the plexus upon the 
vertex of the head, and descends behind the ear to the temporo-maxillary 
vein, immediately before that vessel merges in the external jugular. It 
receives in its course the veins from the external ear and the stylo-mastoid 
vein. 

The Occipital vein commencing posteriorly in the plexus of the vertex 
of the head, follows the direction of the occipital artery, and passing deeply 
beneath the muscles of the back part of the neck, terminates in the internal 
jugular vein. This vein communicates with the lateral sinus by means of 
a large branch which passes through the mastoid foramen, the mastoid vein. 

VEINS OF THE DIPLOE. 

The diploe of the bones of the head is furnished in the adult with irregu- 
lar sinuses, which are formed by a continuation of the internal coat of the 
29 w 



338 



SINUSES OF THE DURA MATER. 



veins into the osseous canals in which they are lodged. At the middle 
period of life these sinuses are confined to the particular bones ; but in old 
age, after the ossification of the sutures, they maybe traced from one bone 
to the next. They receive their blood from the capillaries supplying the 
cellular structure of the diploe, and terminate externally in the veins of the 
pericranium, and internally in the veins and sinuses of the dura mater. 
These veins are separated from the bony walls of the canals by a thin layer 
of medulla. 

CEREBRAL AND CEREBELLAR VEINS. 

The cerebral veins are remarkable for the absence of valves, and for the 
extreme tenuity of their coats. They may be arranged into the superficial, 
and deep or ventricular veins. 

The Superficial cerebral veins are situated on the surface of the hemi- 
spheres, lying in the grooves formed by the convexities of the convolutions. 
They are named from the position which they may chance to occupy upon 
the surface of this organ, either superior or inferior, internal or external, 
anterior or posterior. 

The Superior cerebral veins, seven or eight in number on each side, pass 
obliquely forwards, and terminate in the superior longitudinal sinus, in the 
opposite direction to the course of the stream of blood in the sinus. 

The Deep or Ventricular veins commence within the lateral ventricles by 
the veins of the corpora striata and those of the choroid plexus, which unite 
to form the two vense Galeni. 

The Vence Galeni pass backwards in the structure of the velum interpo- 
situm; and escaping through the fissure of Bichat, terminate in the straight 
sinus. 

The Cerebellar veins are disposed, like those of the cerebrum, on the 
surface of the lobes of the cerebellum ; they are situated some upon the 
superior, and some upon the inferior surface, while others occupy the 
borders of the organ. They terminate in the lateral and petrosal sinuses. 

SINUSES OF THE DURA MATER. 

The sinuses of the dura mater are irregular channels, formed by the 
splitting of the layers of that membrane, and lined upon their inner surface 
by a continuation of the internal coat of the veins. They may be divided 
into two groups: — 1. Those situated at the upper and back part of the 
skull. 2. The sinuses at the base of the skull. The former are, the 

Superior longitudinal sinus, 
Inferior longitudinal sinus, 
Straight sinus, 
Occipital sinuses, 
Lateral sinuses. 

The Superior longitudinal sinus is situated in the attached margin of 
the falx cerebri, and extends along the middle line of the arch of the skull, 
from the foramen caecum in the frontal, to the inner tuberosity of the occi- 
pital bone, where it divides into the two lateral sinuses. It is triangular 
in form, is small in front, and increases gradually in size as it passes 
backwards ; it receives the superior cerebral veins, which open into it 
obliquely, numerous smaP veins from the diploe, and near the posterior 



LATERAL SINUSES. 



339 



Fig. 162. 




extremity of the sagittal suture 
the parietal veins, from the peri- 
cranium and scalp. Examined 
in its interior, it presents numer- 
ous transverse fibrous bands (tra- 
becular), the chordae Willisii, 
which are stretched across its 
inferior angle ; and some small 
white granular masses, the glan- 
dulae Pacchioni ; the oblique 
openings of the cerebral veins, 
with their valve-like margin, are 
also seen on the walls of the 
sinus. 

The termination of the supe- 
rior longitudinal sinus in the two 
lateral sinuses forms a considera- 
ble dilatation, into which the straight sinus opens from the front, and the 
occipital sinuses from below. This dilatation is named the torcular 
Herophili y \ and is the point of communication of six sinuses, the superior 
longitudinal, two lateral, two occipital, and the straight. 

The Inferior longitudinal sinus is situated in the free margin of the falx 
cerebri ; it is cylindrical in form, and extends from near the crista galli to 
the anterior border of the tentorium, where it terminates in the straight 
sinus. It receives in its course several veins from the falx. 

The Straight or fourth sinus is the sinus of the tentorium ; it is situated 
at the line of union of the falx with the tentorium ; is prismoid in form, 
and extends across the tentorium, from the termination of the inferior lon- 
gitudinal sinus to the torcular Herophili. It receives the vense Galeni, 
the cerebral veins from the inferior part of the posterior lobes, and the 
superior cerebellar veins. 

The Occipital sinuses are two canals of small size, situated in the at- 
tached border of the falx cerebelli ; they commence by several small veins 
around the foramen magnum, and terminate by separate openings in the 
torcular Herophili. They not unfrequently communicate with the termi- 
nation of the lateral sinuses. 

The Lateral sinuses, commencing at the torcular Herophili, pass hori- 
zontally outwards, in the attached margin of the tentorium, and then curve 
downwards and inwards along the base of the petrous portion of the tem- 
poral bone, at each side, to the foramina lacera posteriora, where they ter- 
minate in the internal jugular veins. Each sinus rests in its course on the 
transverse groove of the occipital bone, posterior inferior angle of the 
parietal, mastoid portion of the temporal, and again on the occipital bone. 
They receive the cerebral veins from the inferior surface of the posterior 

• The sinuses of the upper and back part of the skull. 1. The superior longitudinal 
sinus. 2, 2. The cerebral veins opening into the sinus from behind forwards. 3. The 
falx cerebri. 4. The inferior longitudinal sinus. 5. The straight or fourth sinus. 6. 
The venae Galeni. 7. The torcular Herophili. 8. The two lateral sinuses, with the 
occipital sinuses between them. 9. The termination of the inferior petrosal sinus of 
one side. 10. The dilatations corresponding with the jugular fossae. 11. The internal 
jugular veins. 

j- Torcular (a press), from a supposition entertained by the older anatomists that the 
columns of blood, coming in different directions, compressed each other at this point. 



340 



SUPERIOR PETROSAL SINUSES. 



lobes, the inferior cerebellar veins, the superior petrosal sinuses, the mas- 
toid, and posterior condyloid veins, and at their termination, the inferior 
petrosal sinuses. These sinuses are often unequal in size, the right being 
larger than the left. 

The sinuses of the base of the skull are the — 

Cavernous, 
Inferior petrosal, 
Circular, 

Superior petrosal, 
Transverse. 

The Cavernous sinuses are named from presenting a structure similar to 
that of the corpus cavernosum penis. They are situated on each side of 
the sella turcica, receiving, anteriorly, the ophthalmic veins through the 
sphenoidal fissures, and terminating posteriorly in the inferior petrosal 
sinuses. In the internal wall of each cavernous sinus is the internal carotid 
artery, accompanied by several filaments of the carotid plexus, and crossed 
by the sixth nerve ; and, in its external wall, the third, fourth, and oph- 
thalmic nerves. These structures are separated from the blood flowing 
through the sinus, by the tubular lining membrane. The cerebral veins 
from the under surface of the anterior lobes open into the cavernous 
sinuses. They communicate by means of the ophthalmic with the facial 
veins, by the circular sinus with each other, and by the superior petrosal 
with the lateral sinuses. 

The Inferior petrosal sinuses are the con- 
tmuations of the cavernous sinuses back- 
wards along the lower border of the petrous 
portion of the temporal bone at each side of 
the base of the skull, to the foramina lacera 
posteriora, where they terminate with the 
lateral sinuses in the commencement of the 
internal jugular veins. 

The Circular sinus (sinus of Ridley) is 
situated in the sella turcica, surrounding the 
pituitary gland, and communicating on each 
side with the cavernous sinus. The poste- 
rior segment is larger than the anterior. 
The Superior petrosal sinuses pass ob- 
|4 liquely backwards along the attached border 
I'm] of the tentorium, on the upper margin of the 
n' 1 *' petrous portion of the temporal bone, and 
establish a communication between the ca- 
vernous and lateral sinus at each side. They 
receive one or two cerebral veins from the 
inferior part of the middle lobes, and a cerebellar vein from the anterior 
border of the cerebellum. Near the extremity of the petrous bone these 
sinuses cross the oval aperture which transmits the fifth nerve. 

* The sinuses of the base of the skull. 1. The ophthalmic veins. 2. The cavernous 
sinus of one side. 3. The circular sinus ; the figure occupies the position of the pituitary 
gland in the sella turcica. 4. The inferior petrosal sinus. 5. The transverse or ante- 
rior occipital sinus. 6. The superior petrosal sinus. 7. The internal jugular vein. 
8. The foramen magnum. 9. The occipital sinuses. 10. The torcular Herophili. 11, 
11. The lateral sinuses. 




VEINS OF THE NECK. 341 

The Transverse sinus (basilar, anterior occipital) passes transversely 
across the basilar process of the occipital bone, forming a communication 
between the two inferior petrosal sinuses. Sometimes there are two si- 
nuses in this situation. 

VEINS OF THE NECK. 

The veins of the neck w T hich return the blood from the head are the — 

External jugular, 
Anterior jugular, 
Internal jugular, 
Vertebral. 

The External jugular vein is formed by the union of the posterior auri- 
cular vein with the temporo-maxillary, and commences at the lower bor- 
der of the parotid gland, in front of the stemo-mastoid muscle. It de- 
scends the neck in the direction of a line drawn from the angle of the 
lower jaw to the middle of the clavicle, crosses the sterno-mastoid, and 
terminates, near the posterior and inferior attachment of that muscle, in 
the subclavian vein. In its course downwards it lies upon the anterior 
lamella of the deep cervical fascia, which separates it from the sterno- 
mastoid muscle, and is covered in by the platysma myoides and superfi- 
cial fascia. At the root of the neck it pierces the deep cervical fascia ; it 
is accompanied, for the upper half of its course, by the auricularis magnus 
nerve. The branches which it receives are the occipital cutaneous and 
posterior cervical cutaneous, and, near its termination, the supra and pos- 
terior scapular. 

The external jugular vein is very variable in size, and is occasionally 
replaced by two veins. In the parotid gland it receives a large commu- 
nicating branch from the internal jugular vein. 

The interior jugular vein is a trunk of variable size, which collects the 
blood from the integument and superficial structures on the fore part of 
the neck. It passes downwards along the anterior border of the sterno- 
mastoid muscle, and opens into the subclavian vein, near the termination 
of the external jugular. The two veins communicate with each other, 
and with the external and internal jugular vein. 

The Internal jugular vein, formed by the convergence of the lateral and 
inferior petrosal sinus, commences at the foramen lacerum posterius on 
each side of the base of the skull, and descends the side of the neck, 
lying, in the first instance, to the outer side of the internal carotid, and 
then upon the outer side of the common carotid artery to the root of the 
neck, where it unites with the subclavian, and constitutes the vena inno- 
minata. At its commencement, the internal jugular vein is posterior and 
external to the internal carotid artery, and the eighth and ninth pairs of 
nerves ; lower down, the vein and artery are on the same plane, the glosso- 
pharyngeal and hypoglossal nerves passing forwards between them, the 
pneumogastric being between and behind in the same sheath, and the 
nervus accessorius crossing obliquely behind the vein. 

The Branches which the internal jugular receives in its course are, the 
facial, the lingual, the inferior pharyngeal, the occipital, and the superior 
and inferior thyroid veins. 

The Vertebral vein descends by the side of the vertebral artery in the 
canal formed by the foramina in the transverse processes of the cervical 
29* 



342 



VEINS OF THE UPPER EXTREMITY. 



vertebrae, and terminates at the root of the neck in the commencement of 
the vena innominata. In the lower part of the vertebral canal it frequently 
divides into two branches, one of which advances forwards, while the 
other passes through the foramen in the transverse process of the seventh 
cervical vertebra, before opening into the vena innominata. 

The Branches w T hich it receives in its course are the posterior condyloid 
vein, muscular branches, the cervical meningo-rachidian veins, and near 
its termination, the superficial and deep cervical veins. 

The Inferior thyroid veins, two, and frequently more in number, are 
situated one on each side of the trachea, and receive the venous blood 
from the thyroid gland. They communicate with each other, and with 
the superior thyroid veins, and form a plexus upon the front of the trachea. 
The right vein terminates in the right vena innominata, just at its union 
with the superior cava, and the left in the left vena innominata. 



VEINS OF THE UPPER EXTREMITY. 

The veins of the upper extremity are the deep and superficial. The 
deep veins accompany the branches and trunks of the arteries, and consti- 
tute their venae comites. The venae comites of the radial and ulnar arte- 
ries are enclosed in the same sheath with those vessels, and terminate at 
the bend of the elbow in the brachial veins. The brachial venae comites 
are situated one on each side of the artery, and open into the axillary 
vein ; the axillary becomes the subclavian, and the subclavian unites with 
the internal jugular to form the vena innominata. 

The Superficial veins of the fore-arm are the — 

Anterior ulnar vein, 
Posterior ulnar vein, 
Basilic vein, 
Radial vein, 
Cephalic vein, 
Median vein, 
Median basilic, 
Median cephalic. 

The Anterior ulnar vein collects the venous blood 
from the inner border of the hand, and from the 
vein of the little finger, vena salvatella, and ascends 
the inner side of the fore-arm to the bend of die 
elbow, where it becomes the basilic vein. 

The Posterior ulnar vein, irregular in size, and 
frequently absent, commences upon the inner bor- 
der and posterior aspect of the hand, and ascend- 
ing the fore-arm, terminates in front of the inner 
condyle, in the anterior ulnar vein. 

The Basilic vein (/3a<r»Xixoc;, royal, or principal) 
ascends from the common ulnar vein formed by the 
two preceding, along the inner side of the upper 
arm, and near its middle pierces the fascia ; it then 
passes upwards to the axilla, and becomes the axillary vein. 

* The veins of the fore-arm and bend of the elbow. 1. The radial vein. 2. The 
cephalic vein. 3. The anterior ulnar vein. 4. The posterior ulnar vein. 5. The trunk 
formed by their union. 6. The basilic vein, piercing the deep fascia at 7. 9. A com- 




AXILLARY AND SUBCLAVIAN VEINS. 343 

The Radial vein commences in the large vein of the thumb, on the 
outer and posterior aspect of the hand, and ascends along the outer bor- 
der of the fore-arm to the bend of the elbow, where it becomes the cepha- 
lic vein. 

The Cephalic vein (xspaXr,, the head) ascends along the outer side of 
the arm to its upper third ; it then enters .the groove between the pectora- 
lis major and deltoid muscle, where it is in relation with the descending 
branch of the thoracico-acromialis artery, and terminates beneath the cla- 
vicle in the subclavian vein. A large communicating branch sometimes 
crosses the clavicle between the external jugular and this vein, which 
gives it the appearance of being derived directly from the head — hence 
its appellation. 

The Median vein is intermediate in position between the anterior ulnar 
and radial vein ; it collects the blood from the anterior aspect of the fore- 
arm, communicating with the two preceding. At the bend of the elbow 
it receives a branch from the deep veins, and divides into two branches, 
the median cephalic and median basilic. 

The Median cephalic vein, generally the smaller of the two, passes 
obliquely outwards, in the groove between the biceps and supinator longus, 
to join the cephalic vein. The branches of the external cutaneous nerve 
pass behind it. 

The Median basilic vein passes obliquely inwards, in the groove be- 
tween the biceps and pronator radii teres, and terminates in the basilic 
vein. This vein is crossed by one or two filaments of the internal cuta- 
neous nerve, and is separated from the brachial artery by the aponeurotic 
slip given off by the tendon of the biceps. 

AXILLARY VEIN. 

The axillary vein is formed by the union of the venae comites of the 
brachial artery with the basilic vein. It lies in front of the artery, receives 
numerous branches from the collateral veins of the branches of the axillary 
artery ; and at the lower border of the first rib becomes the subclavian 
vein. 

SUBCLAVIAN VEIN. 

The subclavian vein crosses over the first rib and beneath the clavicle, 
and unites with the internal jugular vein to form the vena innominata. It 
lies at first in front of the subclavian artery, and then in front of the sca- 
lenus anticus, which separates it from that vessel. The phrenic and 
pneumogastric nerves pass between the artery and vein. The veins open- 
ing into the subclavian are the cephalic below the clavicle, and the external 
and anterior jugulars above ; occasionally some small veins from the 
neighbouring parts also terminate in it. 

municating branch between the deep veins of the fore-arm and the upper part of the 
median vein. 10. The median cephalic vein. 11. The median basilic. 12. A slight 
convexity of the deep fascia, formed by the brachial artery. 13. The process of fascia, 
derived from the tendon of the biceps, which separates the median basilic vein from 
the brachial artery. 14. The external cutaneous nerve, piercing the deep fascia, and 
dividing into two branches, which pass behind the median cephalic vein. 15. The in- 
ternal cutaneous nerve, dividing into branches, which pass in front of the median basi- 
lic vein. 16. The intercosto-humeral cutaneous nerve. 17. The spiral cutaneous nerve, 
a branch of the muscuio-spiral. 



344 



FEMORAL VEIN VEINS OF THE TRUNK. 



VEINS OF THE LOWER EXTREMITY. 



The veins of the lower extremity are the deep and superficial. The 
deep veins accompany the branches of the arteries in pairs, and form the 
venae comites of the anterior and posterior tibial and peroneal arteries. 
These veins unite in the popliteal region to form a single vein of large 
size, the popliteal, which successively becomes in its course the femoral 
and the external iliac vein. 



POPLITEAL VEIN. 

The popliteal vein ascends through the popliteal region, lying, in the 
first instance, directly upon the artery, and then getting somewhat to its 
outer side. It receives several muscular and articular branches, and the 
external saphenous vein. The valves in this vein are four or five in 
number. 

FEMORAL VEIN. 

The femoral vein, passing through the opening in the adductor magnus 
muscle, ascends the thigh in the sheath of the femoral artery, and entering 
the pelvis beneath Poupart's ligament, becomes the external iliac vein. 
In the lower part of its course it is situated upon the outer side of the 
artery ; it then becomes placed behind that vessel, and, at Poupart's liga- 
ment, lies to its inner side. It receives the muscular veins, and the pro- 
funda, and, through the saphenous opening, the internal saphenous vein. 
The valves in this vein are four or five in number. 

The Profunda vein is formed by the convergence of the numerous small 
veins which accompany the branches of the artery ; it is a vein of large 
size, lying in front of the profunda artery, and it terminates in the femoral 
at about an inch and a half below Poupart's ligament. 

The Superficial veins are the external or short, and the internal or long 
saphenous. 

The External saphenous vein collects the blood from the outer side of 
the foot and leg. It passes behind the outer ankle, ascends along the 
posterior aspect of the leg, lying in the groove between the two bellies of 
the gastrocnemius muscle, and pierces the deep fascia in the popliteal 
region to join the popliteal vein. It receives several cutaneous branches 
in the popliteal region before passing through the deep fascia, and is ac- 
companied in its course by the external saphenous nerve. 

The Internal saphenous vein commences upon the dorsum and inner 
side of the foot. It ascends in front of the inner ankle, and along the 
inner side of the leg ; it then passes behind the inner condyle of the femur 
and along the inner side of the thigh to the saphenous opening, where it 
pierces the sheath of the femoral vessels, and terminates in the femoral 
vein, at about one inch and a half below Poupart's ligament. 

It receives in its course the cutaneous veins of the leg and thigh, and 
communicates freely with the deep veins. At the saphenous opening it 
is joined by the superficial epigastric and circumflexa ilii veins, and by 
the external pudic. The situation of this vein in the thigh is not unfre- 
quently occupied by two or even three trunks of nearly equal size. 

VEINS OF THE TRUNK. 

The veins of the trunk maybe divided into, 1. The superior vena cava, 
with its formative branches. 2. The inferior vena cava, with its formative 



SUPERIOR AND INFERIOR VENjE CAV^E. 345 

branches. 3. The azygos veins. 4. The vertebral and spinal veins. 5. 
The cardiac veins. 6. The portal vein. 7. The pulmonary veins. 

SUPERIOR VENA CAVA, WITH ITS FORMATIVE 

BRANCHES. 

Vence Innominatce. 

The Vence Innominatce are two large trunks, formed by the union of 
the internal jugular and subclavian vein, at each side of the root of the 
neck. 

The Right vena innominata, about an inch and a quarter in length, lies 
superficially and externally to the arteria innominata, and descends almost 
vertically to unite with its fellow of the opposite side in the formation of 
the superior cava. At the junction of the jugular and subclavian veins it 
receives from behind the ductus lymphaticus dexter, and lower down it 
has opening into it the right vertebral, right internal mammary , and right 
inferior thyroid vein. 

The Left vena innominata, considerably longer than the right, extends 
almost horizontally across the roots of the three great arteries arising from 
the arch of the aorta, to the right side of the mediastinum, where it unites 
with the right vena innominata, to constitute the superior cava. 

It is in relation in front with the left sterno-clavicular articulation and 
the first piece of the sternum. At its commencement it receives the tho- 
racic duct which opens into it from behind, and in its course is joined by 
the left vertebral, left inferior thyroid, left mammary, and by the superior 
intercostal vein. It also receives some small veins from the mediastinum 
and thymus gland. There are no valves in the venae innominatae. 

SUPERIOR VENA CAVA. 

The superior cava is a short trunk about three inches in length, formed 
by the junction of the two venae innominatae. It descends perpendicularly 
on the right side of the mediastinum, and entering the pericardium termi- 
nates in the upper part of the right auricle. 

It is in relation in front with the thoracic fascia, which separates it from 
the thymus gland, and with the pericardium ; behind with the right pulmo- 
nary artery, and right superior pulmon